linux/Documentation/kernel-parameters.txt

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Kernel Parameters
~~~~~~~~~~~~~~~~~
The following is a consolidated list of the kernel parameters as implemented
(mostly) by the __setup() macro and sorted into English Dictionary order
(defined as ignoring all punctuation and sorting digits before letters in a
case insensitive manner), and with descriptions where known.
Module parameters for loadable modules are specified only as the
parameter name with optional '=' and value as appropriate, such as:
modprobe usbcore blinkenlights=1
Module parameters for modules that are built into the kernel image
are specified on the kernel command line with the module name plus
'.' plus parameter name, with '=' and value if appropriate, such as:
usbcore.blinkenlights=1
Hyphens (dashes) and underscores are equivalent in parameter names, so
log_buf_len=1M print-fatal-signals=1
can also be entered as
log-buf-len=1M print_fatal_signals=1
This document may not be entirely up to date and comprehensive. The command
"modinfo -p ${modulename}" shows a current list of all parameters of a loadable
module. Loadable modules, after being loaded into the running kernel, also
reveal their parameters in /sys/module/${modulename}/parameters/. Some of these
parameters may be changed at runtime by the command
"echo -n ${value} > /sys/module/${modulename}/parameters/${parm}".
The parameters listed below are only valid if certain kernel build options were
enabled and if respective hardware is present. The text in square brackets at
the beginning of each description states the restrictions within which a
parameter is applicable:
ACPI ACPI support is enabled.
AGP AGP (Accelerated Graphics Port) is enabled.
ALSA ALSA sound support is enabled.
APIC APIC support is enabled.
APM Advanced Power Management support is enabled.
AVR32 AVR32 architecture is enabled.
AX25 Appropriate AX.25 support is enabled.
BLACKFIN Blackfin architecture is enabled.
DRM Direct Rendering Management support is enabled.
EDD BIOS Enhanced Disk Drive Services (EDD) is enabled
EFI EFI Partitioning (GPT) is enabled
EIDE EIDE/ATAPI support is enabled.
FB The frame buffer device is enabled.
gcov: add gcov profiling infrastructure Enable the use of GCC's coverage testing tool gcov [1] with the Linux kernel. gcov may be useful for: * debugging (has this code been reached at all?) * test improvement (how do I change my test to cover these lines?) * minimizing kernel configurations (do I need this option if the associated code is never run?) The profiling patch incorporates the following changes: * change kbuild to include profiling flags * provide functions needed by profiling code * present profiling data as files in debugfs Note that on some architectures, enabling gcc's profiling option "-fprofile-arcs" for the entire kernel may trigger compile/link/ run-time problems, some of which are caused by toolchain bugs and others which require adjustment of architecture code. For this reason profiling the entire kernel is initially restricted to those architectures for which it is known to work without changes. This restriction can be lifted once an architecture has been tested and found compatible with gcc's profiling. Profiling of single files or directories is still available on all platforms (see config help text). [1] http://gcc.gnu.org/onlinedocs/gcc/Gcov.html Signed-off-by: Peter Oberparleiter <oberpar@linux.vnet.ibm.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Huang Ying <ying.huang@intel.com> Cc: Li Wei <W.Li@Sun.COM> Cc: Michael Ellerman <michaele@au1.ibm.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Heiko Carstens <heicars2@linux.vnet.ibm.com> Cc: Martin Schwidefsky <mschwid2@linux.vnet.ibm.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: WANG Cong <xiyou.wangcong@gmail.com> Cc: Sam Ravnborg <sam@ravnborg.org> Cc: Jeff Dike <jdike@addtoit.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-17 23:28:08 +00:00
GCOV GCOV profiling is enabled.
HW Appropriate hardware is enabled.
IA-64 IA-64 architecture is enabled.
IMA Integrity measurement architecture is enabled.
IOSCHED More than one I/O scheduler is enabled.
IP_PNP IP DHCP, BOOTP, or RARP is enabled.
IPV6 IPv6 support is enabled.
ISAPNP ISA PnP code is enabled.
ISDN Appropriate ISDN support is enabled.
JOY Appropriate joystick support is enabled.
KGDB Kernel debugger support is enabled.
KVM Kernel Virtual Machine support is enabled.
LIBATA Libata driver is enabled
LP Printer support is enabled.
LOOP Loopback device support is enabled.
M68k M68k architecture is enabled.
These options have more detailed description inside of
Documentation/m68k/kernel-options.txt.
MCA MCA bus support is enabled.
MDA MDA console support is enabled.
MOUSE Appropriate mouse support is enabled.
MSI Message Signaled Interrupts (PCI).
MTD MTD (Memory Technology Device) support is enabled.
NET Appropriate network support is enabled.
NUMA NUMA support is enabled.
NFS Appropriate NFS support is enabled.
OSS OSS sound support is enabled.
PV_OPS A paravirtualized kernel is enabled.
PARIDE The ParIDE (parallel port IDE) subsystem is enabled.
PARISC The PA-RISC architecture is enabled.
PCI PCI bus support is enabled.
PCIE PCI Express support is enabled.
PCMCIA The PCMCIA subsystem is enabled.
PNP Plug & Play support is enabled.
PPC PowerPC architecture is enabled.
PPT Parallel port support is enabled.
PS2 Appropriate PS/2 support is enabled.
RAM RAM disk support is enabled.
S390 S390 architecture is enabled.
SCSI Appropriate SCSI support is enabled.
A lot of drivers have their options described inside
the Documentation/scsi/ sub-directory.
SECURITY Different security models are enabled.
SELINUX SELinux support is enabled.
APPARMOR AppArmor support is enabled.
SERIAL Serial support is enabled.
SH SuperH architecture is enabled.
SMP The kernel is an SMP kernel.
SPARC Sparc architecture is enabled.
SWSUSP Software suspend (hibernation) is enabled.
SUSPEND System suspend states are enabled.
FTRACE Function tracing enabled.
TPM TPM drivers are enabled.
TS Appropriate touchscreen support is enabled.
UMS USB Mass Storage support is enabled.
USB USB support is enabled.
USBHID USB Human Interface Device support is enabled.
V4L Video For Linux support is enabled.
VGA The VGA console has been enabled.
VT Virtual terminal support is enabled.
WDT Watchdog support is enabled.
XT IBM PC/XT MFM hard disk support is enabled.
X86-32 X86-32, aka i386 architecture is enabled.
X86-64 X86-64 architecture is enabled.
More X86-64 boot options can be found in
Documentation/x86/x86_64/boot-options.txt .
X86 Either 32bit or 64bit x86 (same as X86-32+X86-64)
XEN Xen support is enabled
In addition, the following text indicates that the option:
BUGS= Relates to possible processor bugs on the said processor.
KNL Is a kernel start-up parameter.
BOOT Is a boot loader parameter.
Parameters denoted with BOOT are actually interpreted by the boot
loader, and have no meaning to the kernel directly.
Do not modify the syntax of boot loader parameters without extreme
need or coordination with <Documentation/x86/boot.txt>.
There are also arch-specific kernel-parameters not documented here.
See for example <Documentation/x86/x86_64/boot-options.txt>.
Note that ALL kernel parameters listed below are CASE SENSITIVE, and that
a trailing = on the name of any parameter states that that parameter will
be entered as an environment variable, whereas its absence indicates that
it will appear as a kernel argument readable via /proc/cmdline by programs
running once the system is up.
The number of kernel parameters is not limited, but the length of the
complete command line (parameters including spaces etc.) is limited to
a fixed number of characters. This limit depends on the architecture
and is between 256 and 4096 characters. It is defined in the file
./include/asm/setup.h as COMMAND_LINE_SIZE.
acpi= [HW,ACPI,X86]
Advanced Configuration and Power Interface
Format: { force | off | strict | noirq | rsdt }
force -- enable ACPI if default was off
off -- disable ACPI if default was on
noirq -- do not use ACPI for IRQ routing
strict -- Be less tolerant of platforms that are not
strictly ACPI specification compliant.
rsdt -- prefer RSDT over (default) XSDT
copy_dsdt -- copy DSDT to memory
See also Documentation/power/pm.txt, pci=noacpi
acpi_apic_instance= [ACPI, IOAPIC]
Format: <int>
2: use 2nd APIC table, if available
1,0: use 1st APIC table
default: 0
acpi_backlight= [HW,ACPI]
acpi_backlight=vendor
acpi_backlight=video
If set to vendor, prefer vendor specific driver
(e.g. thinkpad_acpi, sony_acpi, etc.) instead
of the ACPI video.ko driver.
acpi.debug_layer= [HW,ACPI,ACPI_DEBUG]
acpi.debug_level= [HW,ACPI,ACPI_DEBUG]
Format: <int>
CONFIG_ACPI_DEBUG must be enabled to produce any ACPI
debug output. Bits in debug_layer correspond to a
_COMPONENT in an ACPI source file, e.g.,
#define _COMPONENT ACPI_PCI_COMPONENT
Bits in debug_level correspond to a level in
ACPI_DEBUG_PRINT statements, e.g.,
ACPI_DEBUG_PRINT((ACPI_DB_INFO, ...
The debug_level mask defaults to "info". See
Documentation/acpi/debug.txt for more information about
debug layers and levels.
Enable processor driver info messages:
acpi.debug_layer=0x20000000
Enable PCI/PCI interrupt routing info messages:
acpi.debug_layer=0x400000
Enable AML "Debug" output, i.e., stores to the Debug
object while interpreting AML:
acpi.debug_layer=0xffffffff acpi.debug_level=0x2
Enable all messages related to ACPI hardware:
acpi.debug_layer=0x2 acpi.debug_level=0xffffffff
Some values produce so much output that the system is
unusable. The "log_buf_len" parameter may be useful
if you need to capture more output.
acpi_display_output= [HW,ACPI]
acpi_display_output=vendor
acpi_display_output=video
See above.
acpi_irq_balance [HW,ACPI]
ACPI will balance active IRQs
default in APIC mode
acpi_irq_nobalance [HW,ACPI]
ACPI will not move active IRQs (default)
default in PIC mode
acpi_irq_isa= [HW,ACPI] If irq_balance, mark listed IRQs used by ISA
Format: <irq>,<irq>...
acpi_irq_pci= [HW,ACPI] If irq_balance, clear listed IRQs for
use by PCI
Format: <irq>,<irq>...
acpi_no_auto_ssdt [HW,ACPI] Disable automatic loading of SSDT
acpi_os_name= [HW,ACPI] Tell ACPI BIOS the name of the OS
Format: To spoof as Windows 98: ="Microsoft Windows"
acpi_osi= [HW,ACPI] Modify list of supported OS interface strings
acpi_osi="string1" # add string1 -- only one string
acpi_osi="!string2" # remove built-in string2
acpi_osi= # disable all strings
acpi_pm_good [X86]
Override the pmtimer bug detection: force the kernel
to assume that this machine's pmtimer latches its value
and always returns good values.
acpi_sci= [HW,ACPI] ACPI System Control Interrupt trigger mode
Format: { level | edge | high | low }
acpi_serialize [HW,ACPI] force serialization of AML methods
acpi_skip_timer_override [HW,ACPI]
Recognize and ignore IRQ0/pin2 Interrupt Override.
For broken nForce2 BIOS resulting in XT-PIC timer.
acpi_sleep= [HW,ACPI] Sleep options
Format: { s3_bios, s3_mode, s3_beep, s4_nohwsig,
old_ordering, s4_nonvs, sci_force_enable }
See Documentation/power/video.txt for information on
s3_bios and s3_mode.
s3_beep is for debugging; it makes the PC's speaker beep
as soon as the kernel's real-mode entry point is called.
s4_nohwsig prevents ACPI hardware signature from being
used during resume from hibernation.
old_ordering causes the ACPI 1.0 ordering of the _PTS
control method, with respect to putting devices into
low power states, to be enforced (the ACPI 2.0 ordering
of _PTS is used by default).
nonvs prevents the kernel from saving/restoring the
ACPI NVS memory during suspend/hibernation and resume.
sci_force_enable causes the kernel to set SCI_EN directly
on resume from S1/S3 (which is against the ACPI spec,
but some broken systems don't work without it).
acpi_use_timer_override [HW,ACPI]
Use timer override. For some broken Nvidia NF5 boards
that require a timer override, but don't have HPET
acpi_enforce_resources= [ACPI]
{ strict | lax | no }
Check for resource conflicts between native drivers
and ACPI OperationRegions (SystemIO and SystemMemory
only). IO ports and memory declared in ACPI might be
used by the ACPI subsystem in arbitrary AML code and
can interfere with legacy drivers.
strict (default): access to resources claimed by ACPI
is denied; legacy drivers trying to access reserved
resources will fail to bind to device using them.
lax: access to resources claimed by ACPI is allowed;
legacy drivers trying to access reserved resources
will bind successfully but a warning message is logged.
no: ACPI OperationRegions are not marked as reserved,
no further checks are performed.
add_efi_memmap [EFI; X86] Include EFI memory map in
kernel's map of available physical RAM.
agp= [AGP]
{ off | try_unsupported }
off: disable AGP support
try_unsupported: try to drive unsupported chipsets
(may crash computer or cause data corruption)
ALSA [HW,ALSA]
See Documentation/sound/alsa/alsa-parameters.txt
alignment= [KNL,ARM]
Allow the default userspace alignment fault handler
behaviour to be specified. Bit 0 enables warnings,
bit 1 enables fixups, and bit 2 sends a segfault.
amd_iommu= [HW,X86-84]
Pass parameters to the AMD IOMMU driver in the system.
Possible values are:
fullflush - enable flushing of IO/TLB entries when
they are unmapped. Otherwise they are
flushed before they will be reused, which
is a lot of faster
off - do not initialize any AMD IOMMU found in
the system
amijoy.map= [HW,JOY] Amiga joystick support
Map of devices attached to JOY0DAT and JOY1DAT
Format: <a>,<b>
See also Documentation/kernel/input/joystick.txt
analog.map= [HW,JOY] Analog joystick and gamepad support
Specifies type or capabilities of an analog joystick
connected to one of 16 gameports
Format: <type1>,<type2>,..<type16>
apc= [HW,SPARC]
Power management functions (SPARCstation-4/5 + deriv.)
Format: noidle
Disable APC CPU standby support. SPARCstation-Fox does
not play well with APC CPU idle - disable it if you have
APC and your system crashes randomly.
apic= [APIC,X86-32] Advanced Programmable Interrupt Controller
Change the output verbosity whilst booting
Format: { quiet (default) | verbose | debug }
Change the amount of debugging information output
when initialising the APIC and IO-APIC components.
autoconf= [IPV6]
See Documentation/networking/ipv6.txt.
show_lapic= [APIC,X86] Advanced Programmable Interrupt Controller
Limit apic dumping. The parameter defines the maximal
number of local apics being dumped. Also it is possible
to set it to "all" by meaning -- no limit here.
Format: { 1 (default) | 2 | ... | all }.
The parameter valid if only apic=debug or
apic=verbose is specified.
Example: apic=debug show_lapic=all
apm= [APM] Advanced Power Management
See header of arch/x86/kernel/apm_32.c.
arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
Format: <io>,<irq>,<nodeID>
ataflop= [HW,M68k]
atarimouse= [HW,MOUSE] Atari Mouse
atkbd.extra= [HW] Enable extra LEDs and keys on IBM RapidAccess,
EzKey and similar keyboards
atkbd.reset= [HW] Reset keyboard during initialization
atkbd.set= [HW] Select keyboard code set
Format: <int> (2 = AT (default), 3 = PS/2)
atkbd.scroll= [HW] Enable scroll wheel on MS Office and similar
keyboards
atkbd.softraw= [HW] Choose between synthetic and real raw mode
Format: <bool> (0 = real, 1 = synthetic (default))
atkbd.softrepeat= [HW]
Use software keyboard repeat
autotest [IA64]
baycom_epp= [HW,AX25]
Format: <io>,<mode>
baycom_par= [HW,AX25] BayCom Parallel Port AX.25 Modem
Format: <io>,<mode>
See header of drivers/net/hamradio/baycom_par.c.
baycom_ser_fdx= [HW,AX25]
BayCom Serial Port AX.25 Modem (Full Duplex Mode)
Format: <io>,<irq>,<mode>[,<baud>]
See header of drivers/net/hamradio/baycom_ser_fdx.c.
baycom_ser_hdx= [HW,AX25]
BayCom Serial Port AX.25 Modem (Half Duplex Mode)
Format: <io>,<irq>,<mode>
See header of drivers/net/hamradio/baycom_ser_hdx.c.
boot_delay= Milliseconds to delay each printk during boot.
Values larger than 10 seconds (10000) are changed to
no delay (0).
Format: integer
bootmem_debug [KNL] Enable bootmem allocator debug messages.
bttv.card= [HW,V4L] bttv (bt848 + bt878 based grabber cards)
bttv.radio= Most important insmod options are available as
kernel args too.
bttv.pll= See Documentation/video4linux/bttv/Insmod-options
bttv.tuner= and Documentation/video4linux/bttv/CARDLIST
c101= [NET] Moxa C101 synchronous serial card
cachesize= [BUGS=X86-32] Override level 2 CPU cache size detection.
Sometimes CPU hardware bugs make them report the cache
size incorrectly. The kernel will attempt work arounds
to fix known problems, but for some CPUs it is not
possible to determine what the correct size should be.
This option provides an override for these situations.
capability.disable=
[SECURITY] Disable capabilities. This would normally
be used only if an alternative security model is to be
configured. Potentially dangerous and should only be
used if you are entirely sure of the consequences.
ccw_timeout_log [S390]
See Documentation/s390/CommonIO for details.
cgroups: add cgroup support for enabling controllers at boot time The effects of cgroup_disable=foo are: - foo isn't auto-mounted if you mount all cgroups in a single hierarchy - foo isn't visible as an individually mountable subsystem As a result there will only ever be one call to foo->create(), at init time; all processes will stay in this group, and the group will never be mounted on a visible hierarchy. Any additional effects (e.g. not allocating metadata) are up to the foo subsystem. This doesn't handle early_init subsystems (their "disabled" bit isn't set be, but it could easily be extended to do so if any of the early_init systems wanted it - I think it would just involve some nastier parameter processing since it would occur before the command-line argument parser had been run. Hugh said: Ballpark figures, I'm trying to get this question out rather than processing the exact numbers: CONFIG_CGROUP_MEM_RES_CTLR adds 15% overhead to the affected paths, booting with cgroup_disable=memory cuts that back to 1% overhead (due to slightly bigger struct page). I'm no expert on distros, they may have no interest whatever in CONFIG_CGROUP_MEM_RES_CTLR=y; and the rest of us can easily build with or without it, or apply the cgroup_disable=memory patches. Unix bench's execl test result on x86_64 was == just after boot without mounting any cgroup fs.== mem_cgorup=off : Execl Throughput 43.0 3150.1 732.6 mem_cgroup=on : Execl Throughput 43.0 2932.6 682.0 == [lizf@cn.fujitsu.com: fix boot option parsing] Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: Paul Menage <menage@google.com> Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: Pavel Emelyanov <xemul@openvz.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Hugh Dickins <hugh@veritas.com> Cc: Sudhir Kumar <skumar@linux.vnet.ibm.com> Cc: YAMAMOTO Takashi <yamamoto@valinux.co.jp> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-04 21:29:57 +00:00
cgroup_disable= [KNL] Disable a particular controller
Format: {name of the controller(s) to disable}
{Currently supported controllers - "memory"}
checkreqprot [SELINUX] Set initial checkreqprot flag value.
Format: { "0" | "1" }
See security/selinux/Kconfig help text.
0 -- check protection applied by kernel (includes
any implied execute protection).
1 -- check protection requested by application.
Default value is set via a kernel config option.
Value can be changed at runtime via
/selinux/checkreqprot.
cio_ignore= [S390]
See Documentation/s390/CommonIO for details.
clock= [BUGS=X86-32, HW] gettimeofday clocksource override.
[Deprecated]
Forces specified clocksource (if available) to be used
when calculating gettimeofday(). If specified
clocksource is not available, it defaults to PIT.
Format: { pit | tsc | cyclone | pmtmr }
clocksource= Override the default clocksource
Format: <string>
Override the default clocksource and use the clocksource
with the name specified.
Some clocksource names to choose from, depending on
the platform:
[all] jiffies (this is the base, fallback clocksource)
[ACPI] acpi_pm
[ARM] imx_timer1,OSTS,netx_timer,mpu_timer2,
pxa_timer,timer3,32k_counter,timer0_1
[AVR32] avr32
[X86-32] pit,hpet,tsc,vmi-timer;
scx200_hrt on Geode; cyclone on IBM x440
[MIPS] MIPS
[PARISC] cr16
[S390] tod
[SH] SuperH
[SPARC64] tick
[X86-64] hpet,tsc
clearcpuid=BITNUM [X86]
Disable CPUID feature X for the kernel. See
arch/x86/include/asm/cpufeature.h for the valid bit
numbers. Note the Linux specific bits are not necessarily
stable over kernel options, but the vendor specific
ones should be.
Also note that user programs calling CPUID directly
or using the feature without checking anything
will still see it. This just prevents it from
being used by the kernel or shown in /proc/cpuinfo.
Also note the kernel might malfunction if you disable
some critical bits.
cmo_free_hint= [PPC] Format: { yes | no }
Specify whether pages are marked as being inactive
when they are freed. This is used in CMO environments
to determine OS memory pressure for page stealing by
a hypervisor.
Default: yes
code_bytes [X86] How many bytes of object code to print
in an oops report.
Range: 0 - 8192
Default: 64
com20020= [HW,NET] ARCnet - COM20020 chipset
Format:
<io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]]
com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
Format: <io>[,<irq>]
com90xx= [HW,NET]
ARCnet - COM90xx chipset (memory-mapped buffers)
Format: <io>[,<irq>[,<memstart>]]
condev= [HW,S390] console device
conmode=
console= [KNL] Output console device and options.
tty<n> Use the virtual console device <n>.
ttyS<n>[,options]
ttyUSB0[,options]
Use the specified serial port. The options are of
the form "bbbbpnf", where "bbbb" is the baud rate,
"p" is parity ("n", "o", or "e"), "n" is number of
bits, and "f" is flow control ("r" for RTS or
omit it). Default is "9600n8".
See Documentation/serial-console.txt for more
information. See
Documentation/networking/netconsole.txt for an
alternative.
uart[8250],io,<addr>[,options]
uart[8250],mmio,<addr>[,options]
Start an early, polled-mode console on the 8250/16550
UART at the specified I/O port or MMIO address,
switching to the matching ttyS device later. The
options are the same as for ttyS, above.
If the device connected to the port is not a TTY but a braille
device, prepend "brl," before the device type, for instance
console=brl,ttyS0
For now, only VisioBraille is supported.
consoleblank= [KNL] The console blank (screen saver) timeout in
seconds. Defaults to 10*60 = 10mins. A value of 0
disables the blank timer.
coredump_filter=
[KNL] Change the default value for
/proc/<pid>/coredump_filter.
See also Documentation/filesystems/proc.txt.
cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver
Format:
<first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
crashkernel=nn[KMG]@ss[KMG]
[KNL] Reserve a chunk of physical memory to
hold a kernel to switch to with kexec on panic.
crashkernel=range1:size1[,range2:size2,...][@offset]
[KNL] Same as above, but depends on the memory
in the running system. The syntax of range is
start-[end] where start and end are both
a memory unit (amount[KMG]). See also
Documentation/kdump/kdump.txt for a example.
cs89x0_dma= [HW,NET]
Format: <dma>
cs89x0_media= [HW,NET]
Format: { rj45 | aui | bnc }
dasd= [HW,NET]
See header of drivers/s390/block/dasd_devmap.c.
db9.dev[2|3]= [HW,JOY] Multisystem joystick support via parallel port
(one device per port)
Format: <port#>,<type>
See also Documentation/input/joystick-parport.txt
debug [KNL] Enable kernel debugging (events log level).
[PATCH] lockdep: locking API self tests Introduce DEBUG_LOCKING_API_SELFTESTS, which uses the generic lock debugging code's silent-failure feature to run a matrix of testcases. There are 210 testcases currently: +----------------------- | Locking API testsuite: +------------------------------+------+------+------+------+------+------+ | spin |wlock |rlock |mutex | wsem | rsem | -------------------------------+------+------+------+------+------+------+ A-A deadlock: ok | ok | ok | ok | ok | ok | A-B-B-A deadlock: ok | ok | ok | ok | ok | ok | A-B-B-C-C-A deadlock: ok | ok | ok | ok | ok | ok | A-B-C-A-B-C deadlock: ok | ok | ok | ok | ok | ok | A-B-B-C-C-D-D-A deadlock: ok | ok | ok | ok | ok | ok | A-B-C-D-B-D-D-A deadlock: ok | ok | ok | ok | ok | ok | A-B-C-D-B-C-D-A deadlock: ok | ok | ok | ok | ok | ok | double unlock: ok | ok | ok | ok | ok | ok | bad unlock order: ok | ok | ok | ok | ok | ok | --------------------------------------+------+------+------+------+------+ recursive read-lock: | ok | | ok | --------------------------------------+------+------+------+------+------+ non-nested unlock: ok | ok | ok | ok | --------------------------------------+------+------+------+ hard-irqs-on + irq-safe-A/12: ok | ok | ok | soft-irqs-on + irq-safe-A/12: ok | ok | ok | hard-irqs-on + irq-safe-A/21: ok | ok | ok | soft-irqs-on + irq-safe-A/21: ok | ok | ok | sirq-safe-A => hirqs-on/12: ok | ok | ok | sirq-safe-A => hirqs-on/21: ok | ok | ok | hard-safe-A + irqs-on/12: ok | ok | ok | soft-safe-A + irqs-on/12: ok | ok | ok | hard-safe-A + irqs-on/21: ok | ok | ok | soft-safe-A + irqs-on/21: ok | ok | ok | hard-safe-A + unsafe-B #1/123: ok | ok | ok | soft-safe-A + unsafe-B #1/123: ok | ok | ok | hard-safe-A + unsafe-B #1/132: ok | ok | ok | soft-safe-A + unsafe-B #1/132: ok | ok | ok | hard-safe-A + unsafe-B #1/213: ok | ok | ok | soft-safe-A + unsafe-B #1/213: ok | ok | ok | hard-safe-A + unsafe-B #1/231: ok | ok | ok | soft-safe-A + unsafe-B #1/231: ok | ok | ok | hard-safe-A + unsafe-B #1/312: ok | ok | ok | soft-safe-A + unsafe-B #1/312: ok | ok | ok | hard-safe-A + unsafe-B #1/321: ok | ok | ok | soft-safe-A + unsafe-B #1/321: ok | ok | ok | hard-safe-A + unsafe-B #2/123: ok | ok | ok | soft-safe-A + unsafe-B #2/123: ok | ok | ok | hard-safe-A + unsafe-B #2/132: ok | ok | ok | soft-safe-A + unsafe-B #2/132: ok | ok | ok | hard-safe-A + unsafe-B #2/213: ok | ok | ok | soft-safe-A + unsafe-B #2/213: ok | ok | ok | hard-safe-A + unsafe-B #2/231: ok | ok | ok | soft-safe-A + unsafe-B #2/231: ok | ok | ok | hard-safe-A + unsafe-B #2/312: ok | ok | ok | soft-safe-A + unsafe-B #2/312: ok | ok | ok | hard-safe-A + unsafe-B #2/321: ok | ok | ok | soft-safe-A + unsafe-B #2/321: ok | ok | ok | hard-irq lock-inversion/123: ok | ok | ok | soft-irq lock-inversion/123: ok | ok | ok | hard-irq lock-inversion/132: ok | ok | ok | soft-irq lock-inversion/132: ok | ok | ok | hard-irq lock-inversion/213: ok | ok | ok | soft-irq lock-inversion/213: ok | ok | ok | hard-irq lock-inversion/231: ok | ok | ok | soft-irq lock-inversion/231: ok | ok | ok | hard-irq lock-inversion/312: ok | ok | ok | soft-irq lock-inversion/312: ok | ok | ok | hard-irq lock-inversion/321: ok | ok | ok | soft-irq lock-inversion/321: ok | ok | ok | hard-irq read-recursion/123: ok | soft-irq read-recursion/123: ok | hard-irq read-recursion/132: ok | soft-irq read-recursion/132: ok | hard-irq read-recursion/213: ok | soft-irq read-recursion/213: ok | hard-irq read-recursion/231: ok | soft-irq read-recursion/231: ok | hard-irq read-recursion/312: ok | soft-irq read-recursion/312: ok | hard-irq read-recursion/321: ok | soft-irq read-recursion/321: ok | --------------------------------+-----+---------------- Good, all 210 testcases passed! | --------------------------------+ Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-07-03 07:24:48 +00:00
debug_locks_verbose=
[KNL] verbose self-tests
Format=<0|1>
Print debugging info while doing the locking API
self-tests.
We default to 0 (no extra messages), setting it to
1 will print _a lot_ more information - normally
only useful to kernel developers.
infrastructure to debug (dynamic) objects We can see an ever repeating problem pattern with objects of any kind in the kernel: 1) freeing of active objects 2) reinitialization of active objects Both problems can be hard to debug because the crash happens at a point where we have no chance to decode the root cause anymore. One problem spot are kernel timers, where the detection of the problem often happens in interrupt context and usually causes the machine to panic. While working on a timer related bug report I had to hack specialized code into the timer subsystem to get a reasonable hint for the root cause. This debug hack was fine for temporary use, but far from a mergeable solution due to the intrusiveness into the timer code. The code further lacked the ability to detect and report the root cause instantly and keep the system operational. Keeping the system operational is important to get hold of the debug information without special debugging aids like serial consoles and special knowledge of the bug reporter. The problems described above are not restricted to timers, but timers tend to expose it usually in a full system crash. Other objects are less explosive, but the symptoms caused by such mistakes can be even harder to debug. Instead of creating specialized debugging code for the timer subsystem a generic infrastructure is created which allows developers to verify their code and provides an easy to enable debug facility for users in case of trouble. The debugobjects core code keeps track of operations on static and dynamic objects by inserting them into a hashed list and sanity checking them on object operations and provides additional checks whenever kernel memory is freed. The tracked object operations are: - initializing an object - adding an object to a subsystem list - deleting an object from a subsystem list Each operation is sanity checked before the operation is executed and the subsystem specific code can provide a fixup function which allows to prevent the damage of the operation. When the sanity check triggers a warning message and a stack trace is printed. The list of operations can be extended if the need arises. For now it's limited to the requirements of the first user (timers). The core code enqueues the objects into hash buckets. The hash index is generated from the address of the object to simplify the lookup for the check on kfree/vfree. Each bucket has it's own spinlock to avoid contention on a global lock. The debug code can be compiled in without being active. The runtime overhead is minimal and could be optimized by asm alternatives. A kernel command line option enables the debugging code. Thanks to Ingo Molnar for review, suggestions and cleanup patches. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu> Cc: Greg KH <greg@kroah.com> Cc: Randy Dunlap <randy.dunlap@oracle.com> Cc: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-30 07:55:01 +00:00
debug_objects [KNL] Enable object debugging
no_debug_objects
[KNL] Disable object debugging
debugpat [X86] Enable PAT debugging
decnet.addr= [HW,NET]
Format: <area>[,<node>]
See also Documentation/networking/decnet.txt.
default_hugepagesz=
[same as hugepagesz=] The size of the default
HugeTLB page size. This is the size represented by
the legacy /proc/ hugepages APIs, used for SHM, and
default size when mounting hugetlbfs filesystems.
Defaults to the default architecture's huge page size
if not specified.
dhash_entries= [KNL]
Set number of hash buckets for dentry cache.
digi= [HW,SERIAL]
IO parameters + enable/disable command.
digiepca= [HW,SERIAL]
See drivers/char/README.epca and
Documentation/serial/digiepca.txt.
disable= [IPV6]
See Documentation/networking/ipv6.txt.
disable_ipv6= [IPV6]
See Documentation/networking/ipv6.txt.
disable_mtrr_cleanup [X86]
The kernel tries to adjust MTRR layout from continuous
to discrete, to make X server driver able to add WB
entry later. This parameter disables that.
disable_mtrr_trim [X86, Intel and AMD only]
x86, 32-bit: trim memory not covered by wb mtrrs On some machines, buggy BIOSes don't properly setup WB MTRRs to cover all available RAM, meaning the last few megs (or even gigs) of memory will be marked uncached. Since Linux tends to allocate from high memory addresses first, this causes the machine to be unusably slow as soon as the kernel starts really using memory (i.e. right around init time). This patch works around the problem by scanning the MTRRs at boot and figuring out whether the current end_pfn value (setup by early e820 code) goes beyond the highest WB MTRR range, and if so, trimming it to match. A fairly obnoxious KERN_WARNING is printed too, letting the user know that not all of their memory is available due to a likely BIOS bug. Something similar could be done on i386 if needed, but the boot ordering would be slightly different, since the MTRR code on i386 depends on the boot_cpu_data structure being setup. This patch fixes a bug in the last patch that caused the code to run on non-Intel machines (AMD machines apparently don't need it and it's untested on other non-Intel machines, so best keep it off). Further enhancements and fixes from: Yinghai Lu <Yinghai.Lu@Sun.COM> Andi Kleen <ak@suse.de> Signed-off-by: Jesse Barnes <jesse.barnes@intel.com> Tested-by: Justin Piszcz <jpiszcz@lucidpixels.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Yinghai Lu <yhlu.kernel@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-01-30 12:33:18 +00:00
By default the kernel will trim any uncacheable
memory out of your available memory pool based on
MTRR settings. This parameter disables that behavior,
possibly causing your machine to run very slowly.
disable_timer_pin_1 [X86]
Disable PIN 1 of APIC timer
Can be useful to work around chipset bugs.
dma_debug=off If the kernel is compiled with DMA_API_DEBUG support,
this option disables the debugging code at boot.
dma_debug_entries=<number>
This option allows to tune the number of preallocated
entries for DMA-API debugging code. One entry is
required per DMA-API allocation. Use this if the
DMA-API debugging code disables itself because the
architectural default is too low.
dma_debug_driver=<driver_name>
With this option the DMA-API debugging driver
filter feature can be enabled at boot time. Just
pass the driver to filter for as the parameter.
The filter can be disabled or changed to another
driver later using sysfs.
dscc4.setup= [NET]
dynamic_printk Enables pr_debug()/dev_dbg() calls if
CONFIG_DYNAMIC_PRINTK_DEBUG has been enabled.
These can also be switched on/off via
<debugfs>/dynamic_printk/modules
earlycon= [KNL] Output early console device and options.
uart[8250],io,<addr>[,options]
uart[8250],mmio,<addr>[,options]
uart[8250],mmio32,<addr>[,options]
Start an early, polled-mode console on the 8250/16550
UART at the specified I/O port or MMIO address.
MMIO inter-register address stride is either 8bit (mmio)
or 32bit (mmio32).
The options are the same as for ttyS, above.
earlyprintk= [X86,SH,BLACKFIN]
earlyprintk=vga
earlyprintk=serial[,ttySn[,baudrate]]
earlyprintk=ttySn[,baudrate]
earlyprintk=dbgp[debugController#]
Append ",keep" to not disable it when the real console
takes over.
Only vga or serial or usb debug port at a time.
Currently only ttyS0 and ttyS1 are supported.
Interaction with the standard serial driver is not
very good.
The VGA output is eventually overwritten by the real
console.
ekgdboc= [X86,KGDB] Allow early kernel console debugging
ekgdboc=kbd
This is desgined to be used in conjunction with
the boot argument: earlyprintk=vga
edd= [EDD]
Format: {"off" | "on" | "skip[mbr]"}
eisa_irq_edge= [PARISC,HW]
See header of drivers/parisc/eisa.c.
elanfreq= [X86-32]
See comment before function elanfreq_setup() in
arch/x86/kernel/cpu/cpufreq/elanfreq.c.
elevator= [IOSCHED]
Format: {"anticipatory" | "cfq" | "deadline" | "noop"}
See Documentation/block/as-iosched.txt and
Documentation/block/deadline-iosched.txt for details.
elfcorehdr= [IA64,PPC,SH,X86]
Specifies physical address of start of kernel core
image elf header. Generally kexec loader will
pass this option to capture kernel.
See Documentation/kdump/kdump.txt for details.
enable_mtrr_cleanup [X86]
The kernel tries to adjust MTRR layout from continuous
to discrete, to make X server driver able to add WB
entry later. This parameter enables that.
enable_timer_pin_1 [X86]
Enable PIN 1 of APIC timer
Can be useful to work around chipset bugs
(in particular on some ATI chipsets).
The kernel tries to set a reasonable default.
enforcing [SELINUX] Set initial enforcing status.
Format: {"0" | "1"}
See security/selinux/Kconfig help text.
0 -- permissive (log only, no denials).
1 -- enforcing (deny and log).
Default value is 0.
Value can be changed at runtime via /selinux/enforce.
erst_disable [ACPI]
Disable Error Record Serialization Table (ERST)
support.
ether= [HW,NET] Ethernet cards parameters
This option is obsoleted by the "netdev=" option, which
has equivalent usage. See its documentation for details.
failslab=
fail_page_alloc=
fail_make_request=[KNL]
General fault injection mechanism.
Format: <interval>,<probability>,<space>,<times>
See also /Documentation/fault-injection/.
floppy= [HW]
See Documentation/blockdev/floppy.txt.
force_pal_cache_flush
[IA-64] Avoid check_sal_cache_flush which may hang on
buggy SAL_CACHE_FLUSH implementations. Using this
parameter will force ia64_sal_cache_flush to call
ia64_pal_cache_flush instead of SAL_CACHE_FLUSH.
ftrace=[tracer]
[FTRACE] will set and start the specified tracer
as early as possible in order to facilitate early
boot debugging.
ftrace_dump_on_oops[=orig_cpu]
[FTRACE] will dump the trace buffers on oops.
If no parameter is passed, ftrace will dump
buffers of all CPUs, but if you pass orig_cpu, it will
dump only the buffer of the CPU that triggered the
oops.
ftrace_filter=[function-list]
[FTRACE] Limit the functions traced by the function
tracer at boot up. function-list is a comma separated
list of functions. This list can be changed at run
time by the set_ftrace_filter file in the debugfs
tracing directory.
ftrace_notrace=[function-list]
[FTRACE] Do not trace the functions specified in
function-list. This list can be changed at run time
by the set_ftrace_notrace file in the debugfs
tracing directory.
ftrace_graph_filter=[function-list]
[FTRACE] Limit the top level callers functions traced
by the function graph tracer at boot up.
function-list is a comma separated list of functions
that can be changed at run time by the
set_graph_function file in the debugfs tracing directory.
gamecon.map[2|3]=
[HW,JOY] Multisystem joystick and NES/SNES/PSX pad
support via parallel port (up to 5 devices per port)
Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5>
See also Documentation/input/joystick-parport.txt
gamma= [HW,DRM]
x86: disable the GART early, 64-bit For K8 system: 4G RAM with memory hole remapping enabled, or more than 4G RAM installed. when try to use kexec second kernel, and the first doesn't include gart_shutdown. the second kernel could have different aper position than the first kernel. and second kernel could use that hole as RAM that is still used by GART set by the first kernel. esp. when try to kexec 2.6.24 with sparse mem enable from previous kernel (from RHEL 5 or SLES 10). the new kernel will use aper by GART (set by first kernel) for vmemmap. and after new kernel setting one new GART. the position will be real RAM. the _mapcount set is lost. Bad page state in process 'swapper' page:ffffe2000e600020 flags:0x0000000000000000 mapping:0000000000000000 mapcount:1 count:0 Trying to fix it up, but a reboot is needed Backtrace: Pid: 0, comm: swapper Not tainted 2.6.24-rc7-smp-gcdf71a10-dirty #13 Call Trace: [<ffffffff8026401f>] bad_page+0x63/0x8d [<ffffffff80264169>] __free_pages_ok+0x7c/0x2a5 [<ffffffff80ba75d1>] free_all_bootmem_core+0xd0/0x198 [<ffffffff80ba3a42>] numa_free_all_bootmem+0x3b/0x76 [<ffffffff80ba3461>] mem_init+0x3b/0x152 [<ffffffff80b959d3>] start_kernel+0x236/0x2c2 [<ffffffff80b9511a>] _sinittext+0x11a/0x121 and [ffffe2000e600000-ffffe2000e7fffff] PMD ->ffff81001c200000 on node 0 phys addr is : 0x1c200000 RHEL 5.1 kernel -53 said: PCI-DMA: aperture base @ 1c000000 size 65536 KB new kernel said: Mapping aperture over 65536 KB of RAM @ 3c000000 So could try to disable that GART if possible. According to Ingo > hm, i'm wondering, instead of modifying the GART, why dont we simply > _detect_ whatever GART settings we have inherited, and propagate that > into our e820 maps? I.e. if there's inconsistency, then punch that out > from the memory maps and just dont use that memory. > > that way it would not matter whether the GART settings came from a [old > or crashing] Linux kernel that has not called gart_iommu_shutdown(), or > whether it's a BIOS that has set up an aperture hole inconsistent with > the memory map it passed. (or the memory map we _think_ i tried to pass > us) > > it would also be more robust to only read and do a memory map quirk > based on that, than actively trying to change the GART so early in the > bootup. Later on we have to re-enable the GART _anyway_ and have to > punch a hole for it. > > and as a bonus, we would have shored up our defenses against crappy > BIOSes as well. add e820 modification for gart inconsistent setting. gart_fix_e820=off could be used to disable e820 fix. Signed-off-by: Yinghai Lu <yinghai.lu@sun.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-01-30 12:33:09 +00:00
gart_fix_e820= [X86_64] disable the fix e820 for K8 GART
Format: off | on
default: on
gcov: add gcov profiling infrastructure Enable the use of GCC's coverage testing tool gcov [1] with the Linux kernel. gcov may be useful for: * debugging (has this code been reached at all?) * test improvement (how do I change my test to cover these lines?) * minimizing kernel configurations (do I need this option if the associated code is never run?) The profiling patch incorporates the following changes: * change kbuild to include profiling flags * provide functions needed by profiling code * present profiling data as files in debugfs Note that on some architectures, enabling gcc's profiling option "-fprofile-arcs" for the entire kernel may trigger compile/link/ run-time problems, some of which are caused by toolchain bugs and others which require adjustment of architecture code. For this reason profiling the entire kernel is initially restricted to those architectures for which it is known to work without changes. This restriction can be lifted once an architecture has been tested and found compatible with gcc's profiling. Profiling of single files or directories is still available on all platforms (see config help text). [1] http://gcc.gnu.org/onlinedocs/gcc/Gcov.html Signed-off-by: Peter Oberparleiter <oberpar@linux.vnet.ibm.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Huang Ying <ying.huang@intel.com> Cc: Li Wei <W.Li@Sun.COM> Cc: Michael Ellerman <michaele@au1.ibm.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Heiko Carstens <heicars2@linux.vnet.ibm.com> Cc: Martin Schwidefsky <mschwid2@linux.vnet.ibm.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: WANG Cong <xiyou.wangcong@gmail.com> Cc: Sam Ravnborg <sam@ravnborg.org> Cc: Jeff Dike <jdike@addtoit.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-17 23:28:08 +00:00
gcov_persist= [GCOV] When non-zero (default), profiling data for
kernel modules is saved and remains accessible via
debugfs, even when the module is unloaded/reloaded.
When zero, profiling data is discarded and associated
debugfs files are removed at module unload time.
gpt [EFI] Forces disk with valid GPT signature but
invalid Protective MBR to be treated as GPT.
hashdist= [KNL,NUMA] Large hashes allocated during boot
are distributed across NUMA nodes. Defaults on
for 64bit NUMA, off otherwise.
Format: 0 | 1 (for off | on)
hcl= [IA-64] SGI's Hardware Graph compatibility layer
hd= [EIDE] (E)IDE hard drive subsystem geometry
Format: <cyl>,<head>,<sect>
hest_disable [ACPI]
Disable Hardware Error Source Table (HEST) support;
corresponding firmware-first mode error processing
logic will be disabled.
highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
size of <nn>. This works even on boxes that have no
highmem otherwise. This also works to reduce highmem
size on bigger boxes.
highres= [KNL] Enable/disable high resolution timer mode.
Valid parameters: "on", "off"
Default: "on"
hisax= [HW,ISDN]
See Documentation/isdn/README.HiSax.
hlt [BUGS=ARM,SH]
hpet= [X86-32,HPET] option to control HPET usage
Format: { enable (default) | disable | force |
verbose }
disable: disable HPET and use PIT instead
force: allow force enabled of undocumented chips (ICH4,
VIA, nVidia)
verbose: show contents of HPET registers during setup
hugepages= [HW,X86-32,IA-64] HugeTLB pages to allocate at boot.
hugepagesz= [HW,IA-64,PPC,X86-64] The size of the HugeTLB pages.
On x86-64 and powerpc, this option can be specified
multiple times interleaved with hugepages= to reserve
huge pages of different sizes. Valid pages sizes on
x86-64 are 2M (when the CPU supports "pse") and 1G
(when the CPU supports the "pdpe1gb" cpuinfo flag)
Note that 1GB pages can only be allocated at boot time
using hugepages= and not freed afterwards.
hvc_iucv= [S390] Number of z/VM IUCV hypervisor console (HVC)
terminal devices. Valid values: 0..8
hvc_iucv_allow= [S390] Comma-separated list of z/VM user IDs.
If specified, z/VM IUCV HVC accepts connections
from listed z/VM user IDs only.
i2c_bus= [HW] Override the default board specific I2C bus speed
or register an additional I2C bus that is not
registered from board initialization code.
Format:
<bus_id>,<clkrate>
i8042.debug [HW] Toggle i8042 debug mode
i8042.direct [HW] Put keyboard port into non-translated mode
i8042.dumbkbd [HW] Pretend that controller can only read data from
keyboard and cannot control its state
(Don't attempt to blink the leds)
i8042.noaux [HW] Don't check for auxiliary (== mouse) port
i8042.nokbd [HW] Don't check/create keyboard port
i8042.noloop [HW] Disable the AUX Loopback command while probing
for the AUX port
i8042.nomux [HW] Don't check presence of an active multiplexing
controller
i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
controllers
i8042.reset [HW] Reset the controller during init and cleanup
i8042.unlock [HW] Unlock (ignore) the keylock
i810= [HW,DRM]
i8k.ignore_dmi [HW] Continue probing hardware even if DMI data
indicates that the driver is running on unsupported
hardware.
i8k.force [HW] Activate i8k driver even if SMM BIOS signature
does not match list of supported models.
i8k.power_status
[HW] Report power status in /proc/i8k
(disabled by default)
i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN
capability is set.
icn= [HW,ISDN]
Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
ide-core.nodma= [HW] (E)IDE subsystem
Format: =0.0 to prevent dma on hda, =0.1 hdb =1.0 hdc
.vlb_clock .pci_clock .noflush .nohpa .noprobe .nowerr
.cdrom .chs .ignore_cable are additional options
See Documentation/ide/ide.txt.
ide-pci-generic.all-generic-ide [HW] (E)IDE subsystem
Claim all unknown PCI IDE storage controllers.
idle= [X86]
Format: idle=poll, idle=mwait, idle=halt, idle=nomwait
Poll forces a polling idle loop that can slightly
improve the performance of waking up a idle CPU, but
will use a lot of power and make the system run hot.
Not recommended.
idle=mwait: On systems which support MONITOR/MWAIT but
the kernel chose to not use it because it doesn't save
as much power as a normal idle loop, use the
MONITOR/MWAIT idle loop anyways. Performance should be
the same as idle=poll.
idle=halt: Halt is forced to be used for CPU idle.
In such case C2/C3 won't be used again.
idle=nomwait: Disable mwait for CPU C-states
ignore_loglevel [KNL]
Ignore loglevel setting - this will print /all/
kernel messages to the console. Useful for debugging.
ihash_entries= [KNL]
Set number of hash buckets for inode cache.
ima_audit= [IMA]
Format: { "0" | "1" }
0 -- integrity auditing messages. (Default)
1 -- enable informational integrity auditing messages.
ima_hash= [IMA]
Format: { "sha1" | "md5" }
default: "sha1"
IMA: Minimal IMA policy and boot param for TCB IMA policy The IMA TCB policy is dangerous. A normal use can use all of a system's memory (which cannot be freed) simply by building and running lots of executables. The TCB policy is also nearly useless because logging in as root often causes a policy violation when dealing with utmp, thus rendering the measurements meaningless. There is no good fix for this in the kernel. A full TCB policy would need to be loaded in userspace using LSM rule matching to get both a protected and useful system. But, if too little is measured before userspace can load a real policy one again ends up with a meaningless set of measurements. One option would be to put the policy load inside the initrd in order to get it early enough in the boot sequence to be useful, but this runs into trouble with the LSM. For IMA to measure the LSM policy and the LSM policy loading mechanism it needs rules to do so, but we already talked about problems with defaulting to such broad rules.... IMA also depends on the files being measured to be on an FS which implements and supports i_version. Since the only FS with this support (ext4) doesn't even use it by default it seems silly to have any IMA rules by default. This should reduce the performance overhead of IMA to near 0 while still letting users who choose to configure their machine as such to inclue the ima_tcb kernel paramenter and get measurements during boot before they can load a customized, reasonable policy in userspace. Signed-off-by: Eric Paris <eparis@redhat.com> Acked-by: Mimi Zohar <zohar@us.ibm.com> Signed-off-by: James Morris <jmorris@namei.org>
2009-05-21 19:47:06 +00:00
ima_tcb [IMA]
Load a policy which meets the needs of the Trusted
Computing Base. This means IMA will measure all
programs exec'd, files mmap'd for exec, and all files
opened for read by uid=0.
init= [KNL]
Format: <full_path>
Run specified binary instead of /sbin/init as init
process.
initcall_debug [KNL] Trace initcalls as they are executed. Useful
for working out where the kernel is dying during
startup.
initrd= [BOOT] Specify the location of the initial ramdisk
inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver
Format: <irq>
intel_iommu= [DMAR] Intel IOMMU driver (DMAR) option
on
Enable intel iommu driver.
off
Disable intel iommu driver.
igfx_off [Default Off]
By default, gfx is mapped as normal device. If a gfx
device has a dedicated DMAR unit, the DMAR unit is
bypassed by not enabling DMAR with this option. In
this case, gfx device will use physical address for
DMA.
forcedac [x86_64]
With this option iommu will not optimize to look
for io virtual address below 32 bit forcing dual
address cycle on pci bus for cards supporting greater
than 32 bit addressing. The default is to look
for translation below 32 bit and if not available
then look in the higher range.
strict [Default Off]
With this option on every unmap_single operation will
result in a hardware IOTLB flush operation as opposed
to batching them for performance.
intremap= [X86-64, Intel-IOMMU]
Format: { on (default) | off | nosid }
on enable Interrupt Remapping (default)
off disable Interrupt Remapping
nosid disable Source ID checking
inttest= [IA64]
iomem= Disable strict checking of access to MMIO memory
strict regions from userspace.
relaxed
iommu= [x86]
off
force
noforce
biomerge
panic
nopanic
merge
nomerge
forcesac
soft
pt [x86, IA64]
io7= [HW] IO7 for Marvel based alpha systems
See comment before marvel_specify_io7 in
arch/alpha/kernel/core_marvel.c.
io_delay= [X86] I/O delay method
0x80
Standard port 0x80 based delay
0xed
Alternate port 0xed based delay (needed on some systems)
x86: provide a DMI based port 0x80 I/O delay override. x86: provide a DMI based port 0x80 I/O delay override. Certain (HP) laptops experience trouble from our port 0x80 I/O delay writes. This patch provides for a DMI based switch to the "alternate diagnostic port" 0xed (as used by some BIOSes as well) for these. David P. Reed confirmed that port 0xed works for him and provides a proper delay. The symptoms of _not_ working are a hanging machine, with "hwclock" use being a direct trigger. Earlier versions of this attempted to simply use udelay(2), with the 2 being a value tested to be a nicely conservative upper-bound with help from many on the linux-kernel mailinglist but that approach has two problems. First, pre-loops_per_jiffy calibration (which is post PIT init while some implementations of the PIT are actually one of the historically problematic devices that need the delay) udelay() isn't particularly well-defined. We could initialise loops_per_jiffy conservatively (and based on CPU family so as to not unduly delay old machines) which would sort of work, but... Second, delaying isn't the only effect that a write to port 0x80 has. It's also a PCI posting barrier which some devices may be explicitly or implicitly relying on. Alan Cox did a survey and found evidence that additionally some drivers may be racy on SMP without the bus locking outb. Switching to an inb() makes the timing too unpredictable and as such, this DMI based switch should be the safest approach for now. Any more invasive changes should get more rigid testing first. It's moreover only very few machines with the problem and a DMI based hack seems to fit that situation. This also introduces a command-line parameter "io_delay" to override the DMI based choice again: io_delay=<standard|alternate> where "standard" means using the standard port 0x80 and "alternate" port 0xed. This retains the udelay method as a config (CONFIG_UDELAY_IO_DELAY) and command-line ("io_delay=udelay") choice for testing purposes as well. This does not change the io_delay() in the boot code which is using the same port 0x80 I/O delay but those do not appear to be a problem as David P. Reed reported the problem was already gone after using the udelay version. He moreover reported that booting with "acpi=off" also fixed things and seeing as how ACPI isn't touched until after this DMI based I/O port switch I believe it's safe to leave the ones in the boot code be. The DMI strings from David's HP Pavilion dv9000z are in there already and we need to get/verify the DMI info from other machines with the problem, notably the HP Pavilion dv6000z. This patch is partly based on earlier patches from Pavel Machek and David P. Reed. Signed-off-by: Rene Herman <rene.herman@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-01-30 12:30:05 +00:00
udelay
Simple two microseconds delay
none
No delay
x86: provide a DMI based port 0x80 I/O delay override. x86: provide a DMI based port 0x80 I/O delay override. Certain (HP) laptops experience trouble from our port 0x80 I/O delay writes. This patch provides for a DMI based switch to the "alternate diagnostic port" 0xed (as used by some BIOSes as well) for these. David P. Reed confirmed that port 0xed works for him and provides a proper delay. The symptoms of _not_ working are a hanging machine, with "hwclock" use being a direct trigger. Earlier versions of this attempted to simply use udelay(2), with the 2 being a value tested to be a nicely conservative upper-bound with help from many on the linux-kernel mailinglist but that approach has two problems. First, pre-loops_per_jiffy calibration (which is post PIT init while some implementations of the PIT are actually one of the historically problematic devices that need the delay) udelay() isn't particularly well-defined. We could initialise loops_per_jiffy conservatively (and based on CPU family so as to not unduly delay old machines) which would sort of work, but... Second, delaying isn't the only effect that a write to port 0x80 has. It's also a PCI posting barrier which some devices may be explicitly or implicitly relying on. Alan Cox did a survey and found evidence that additionally some drivers may be racy on SMP without the bus locking outb. Switching to an inb() makes the timing too unpredictable and as such, this DMI based switch should be the safest approach for now. Any more invasive changes should get more rigid testing first. It's moreover only very few machines with the problem and a DMI based hack seems to fit that situation. This also introduces a command-line parameter "io_delay" to override the DMI based choice again: io_delay=<standard|alternate> where "standard" means using the standard port 0x80 and "alternate" port 0xed. This retains the udelay method as a config (CONFIG_UDELAY_IO_DELAY) and command-line ("io_delay=udelay") choice for testing purposes as well. This does not change the io_delay() in the boot code which is using the same port 0x80 I/O delay but those do not appear to be a problem as David P. Reed reported the problem was already gone after using the udelay version. He moreover reported that booting with "acpi=off" also fixed things and seeing as how ACPI isn't touched until after this DMI based I/O port switch I believe it's safe to leave the ones in the boot code be. The DMI strings from David's HP Pavilion dv9000z are in there already and we need to get/verify the DMI info from other machines with the problem, notably the HP Pavilion dv6000z. This patch is partly based on earlier patches from Pavel Machek and David P. Reed. Signed-off-by: Rene Herman <rene.herman@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-01-30 12:30:05 +00:00
ip= [IP_PNP]
See Documentation/filesystems/nfs/nfsroot.txt.
ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
See comment before ip2_setup() in
drivers/char/ip2/ip2base.c.
irqfixup [HW]
When an interrupt is not handled search all handlers
for it. Intended to get systems with badly broken
firmware running.
irqpoll [HW]
When an interrupt is not handled search all handlers
for it. Also check all handlers each timer
interrupt. Intended to get systems with badly broken
firmware running.
isapnp= [ISAPNP]
Format: <RDP>,<reset>,<pci_scan>,<verbosity>
isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
Format:
<cpu number>,...,<cpu number>
or
<cpu number>-<cpu number>
(must be a positive range in ascending order)
or a mixture
<cpu number>,...,<cpu number>-<cpu number>
This option can be used to specify one or more CPUs
to isolate from the general SMP balancing and scheduling
algorithms. You can move a process onto or off an
"isolated" CPU via the CPU affinity syscalls or cpuset.
<cpu number> begins at 0 and the maximum value is
"number of CPUs in system - 1".
This option is the preferred way to isolate CPUs. The
alternative -- manually setting the CPU mask of all
tasks in the system -- can cause problems and
suboptimal load balancer performance.
iucv= [HW,NET]
js= [HW,JOY] Analog joystick
See Documentation/input/joystick.txt.
keepinitrd [HW,ARM]
kernelcore=nn[KMG] [KNL,X86,IA-64,PPC] This parameter
specifies the amount of memory usable by the kernel
for non-movable allocations. The requested amount is
spread evenly throughout all nodes in the system. The
remaining memory in each node is used for Movable
pages. In the event, a node is too small to have both
kernelcore and Movable pages, kernelcore pages will
take priority and other nodes will have a larger number
of kernelcore pages. The Movable zone is used for the
allocation of pages that may be reclaimed or moved
by the page migration subsystem. This means that
HugeTLB pages may not be allocated from this zone.
Note that allocations like PTEs-from-HighMem still
use the HighMem zone if it exists, and the Normal
zone if it does not.
echi-dbgp: Add kernel debugger support for the usb debug port This patch adds the capability to use the usb debug port with the kernel debugger. It is also still possible to use this functionality with or without the earlyprintk=dbgpX. It is possible to use the kgdbwait boot argument to debug very early in the kernel start up code. There are two ways to use this driver extension with a kernel boot argument. 1) kgdbdbgp=# -- Where # is the number of the usb debug controller You must use sysrq-g to break into the kernel debugger on another connection type other than the dbgp. 2) kgdbdbgp=#debugControlNum#,#Seconds# In this mode, the usb debug port is polled every #Seconds# for character input. It is possible to use gdb or press control-c to break into the kernel debugger. From the implementation perspective there are 3 high level changes. 1) Allow variable retries for the the hardware via dbgp_bulk_read(). The amount of retries for the dbgp_bulk_read() needed to be variable instead of fixed. We do not want to poll at all when the kernel is operating in interrupt driven mode. The polling only occurs if the kernel was booted when specifying some number of seconds via the kgdbdbgp boot argument (IE kgdbdbgp=0,1). In this case the loop count is reduced to 1 so as introduce the smallest amount of latency as possible. 2) Save the bulk IN endpoint address for use by the kgdb code. 3) The addition of the kgdb interface code. This consisted of adding in a character read function for the dbgp as well as a polling thread to allow the dbgp to interrupt the kernel execution. The rest is the typical kgdb I/O api. CC: Eric Biederman <ebiederm@xmission.com> CC: Yinghai Lu <yhlu.kernel@gmail.com> CC: linux-usb@vger.kernel.org Signed-off-by: Jason Wessel <jason.wessel@windriver.com> Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
2010-05-21 02:04:31 +00:00
kgdbdbgp= [KGDB,HW] kgdb over EHCI usb debug port.
Format: <Controller#>[,poll interval]
The controller # is the number of the ehci usb debug
port as it is probed via PCI. The poll interval is
optional and is the number seconds in between
each poll cycle to the debug port in case you need
the functionality for interrupting the kernel with
gdb or control-c on the dbgp connection. When
not using this parameter you use sysrq-g to break into
the kernel debugger.
kgdboc= [KGDB,HW] kgdb over consoles.
Requires a tty driver that supports console polling,
or a supported polling keyboard driver (non-usb).
Serial only format: <serial_device>[,baud]
keyboard only format: kbd
keyboard and serial format: kbd,<serial_device>[,baud]
Optional Kernel mode setting:
kms, kbd format: kms,kbd
kms, kbd and serial format: kms,kbd,<ser_dev>[,baud]
kgdbwait [KGDB] Stop kernel execution and enter the
kernel debugger at the earliest opportunity.
kmac= [MIPS] korina ethernet MAC address.
Configure the RouterBoard 532 series on-chip
Ethernet adapter MAC address.
kmemleak= [KNL] Boot-time kmemleak enable/disable
Valid arguments: on, off
Default: on
kstack=N [X86] Print N words from the kernel stack
in oops dumps.
kvm.ignore_msrs=[KVM] Ignore guest accesses to unhandled MSRs.
Default is 0 (don't ignore, but inject #GP)
kvm.oos_shadow= [KVM] Disable out-of-sync shadow paging.
Default is 1 (enabled)
kvm-amd.nested= [KVM,AMD] Allow nested virtualization in KVM/SVM.
Default is 0 (off)
kvm-amd.npt= [KVM,AMD] Disable nested paging (virtualized MMU)
for all guests.
Default is 1 (enabled) if in 64bit or 32bit-PAE mode
kvm-intel.bypass_guest_pf=
[KVM,Intel] Disables bypassing of guest page faults
on Intel chips. Default is 1 (enabled)
kvm-intel.ept= [KVM,Intel] Disable extended page tables
(virtualized MMU) support on capable Intel chips.
Default is 1 (enabled)
kvm-intel.emulate_invalid_guest_state=
[KVM,Intel] Enable emulation of invalid guest states
Default is 0 (disabled)
kvm-intel.flexpriority=
[KVM,Intel] Disable FlexPriority feature (TPR shadow).
Default is 1 (enabled)
kvm-intel.unrestricted_guest=
[KVM,Intel] Disable unrestricted guest feature
(virtualized real and unpaged mode) on capable
Intel chips. Default is 1 (enabled)
kvm-intel.vpid= [KVM,Intel] Disable Virtual Processor Identification
feature (tagged TLBs) on capable Intel chips.
Default is 1 (enabled)
l2cr= [PPC]
l3cr= [PPC]
lapic [X86-32,APIC] Enable the local APIC even if BIOS
disabled it.
lapic_timer_c2_ok [X86,APIC] trust the local apic timer
in C2 power state.
libata.dma= [LIBATA] DMA control
libata.dma=0 Disable all PATA and SATA DMA
libata.dma=1 PATA and SATA Disk DMA only
libata.dma=2 ATAPI (CDROM) DMA only
libata.dma=4 Compact Flash DMA only
Combinations also work, so libata.dma=3 enables DMA
for disks and CDROMs, but not CFs.
libata.ignore_hpa= [LIBATA] Ignore HPA limit
libata.ignore_hpa=0 keep BIOS limits (default)
libata.ignore_hpa=1 ignore limits, using full disk
libata.noacpi [LIBATA] Disables use of ACPI in libata suspend/resume
when set.
Format: <int>
libata.force= [LIBATA] Force configurations. The format is comma
separated list of "[ID:]VAL" where ID is
PORT[.DEVICE]. PORT and DEVICE are decimal numbers
matching port, link or device. Basically, it matches
the ATA ID string printed on console by libata. If
the whole ID part is omitted, the last PORT and DEVICE
values are used. If ID hasn't been specified yet, the
configuration applies to all ports, links and devices.
If only DEVICE is omitted, the parameter applies to
the port and all links and devices behind it. DEVICE
number of 0 either selects the first device or the
first fan-out link behind PMP device. It does not
select the host link. DEVICE number of 15 selects the
host link and device attached to it.
The VAL specifies the configuration to force. As long
as there's no ambiguity shortcut notation is allowed.
For example, both 1.5 and 1.5G would work for 1.5Gbps.
The following configurations can be forced.
* Cable type: 40c, 80c, short40c, unk, ign or sata.
Any ID with matching PORT is used.
* SATA link speed limit: 1.5Gbps or 3.0Gbps.
* Transfer mode: pio[0-7], mwdma[0-4] and udma[0-7].
udma[/][16,25,33,44,66,100,133] notation is also
allowed.
* [no]ncq: Turn on or off NCQ.
* nohrst, nosrst, norst: suppress hard, soft
and both resets.
* dump_id: dump IDENTIFY data.
If there are multiple matching configurations changing
the same attribute, the last one is used.
memblock=debug [KNL] Enable memblock debug messages.
load_ramdisk= [RAM] List of ramdisks to load from floppy
See Documentation/blockdev/ramdisk.txt.
lockd.nlm_grace_period=P [NFS] Assign grace period.
Format: <integer>
lockd.nlm_tcpport=N [NFS] Assign TCP port.
Format: <integer>
lockd.nlm_timeout=T [NFS] Assign timeout value.
Format: <integer>
lockd.nlm_udpport=M [NFS] Assign UDP port.
Format: <integer>
logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver
Format: <irq>
loglevel= All Kernel Messages with a loglevel smaller than the
console loglevel will be printed to the console. It can
also be changed with klogd or other programs. The
loglevels are defined as follows:
0 (KERN_EMERG) system is unusable
1 (KERN_ALERT) action must be taken immediately
2 (KERN_CRIT) critical conditions
3 (KERN_ERR) error conditions
4 (KERN_WARNING) warning conditions
5 (KERN_NOTICE) normal but significant condition
6 (KERN_INFO) informational
7 (KERN_DEBUG) debug-level messages
log_buf_len=n Sets the size of the printk ring buffer, in bytes.
Format: { n | nk | nM }
n must be a power of two. The default size
is set in the kernel config file.
logo.nologo [FB] Disables display of the built-in Linux logo.
This may be used to provide more screen space for
kernel log messages and is useful when debugging
kernel boot problems.
lp=0 [LP] Specify parallel ports to use, e.g,
lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses
lp=reset first parallel port). 'lp=0' disables the
lp=auto printer driver. 'lp=reset' (which can be
specified in addition to the ports) causes
attached printers to be reset. Using
lp=port1,port2,... specifies the parallel ports
to associate lp devices with, starting with
lp0. A port specification may be 'none' to skip
that lp device, or a parport name such as
'parport0'. Specifying 'lp=auto' instead of a
port specification list means that device IDs
from each port should be examined, to see if
an IEEE 1284-compliant printer is attached; if
so, the driver will manage that printer.
See also header of drivers/char/lp.c.
lpj=n [KNL]
Sets loops_per_jiffy to given constant, thus avoiding
time-consuming boot-time autodetection (up to 250 ms per
CPU). 0 enables autodetection (default). To determine
the correct value for your kernel, boot with normal
autodetection and see what value is printed. Note that
on SMP systems the preset will be applied to all CPUs,
which is likely to cause problems if your CPUs need
significantly divergent settings. An incorrect value
will cause delays in the kernel to be wrong, leading to
unpredictable I/O errors and other breakage. Although
unlikely, in the extreme case this might damage your
hardware.
ltpc= [NET]
Format: <io>,<irq>,<dma>
machvec= [IA64] Force the use of a particular machine-vector
(machvec) in a generic kernel.
Example: machvec=hpzx1_swiotlb
machtype= [Loongson] Share the same kernel image file between different
yeeloong laptop.
Example: machtype=lemote-yeeloong-2f-7inch
max_addr=nn[KMG] [KNL,BOOT,ia64] All physical memory greater
than or equal to this physical address is ignored.
maxcpus= [SMP] Maximum number of processors that an SMP kernel
should make use of. maxcpus=n : n >= 0 limits the
kernel to using 'n' processors. n=0 is a special case,
it is equivalent to "nosmp", which also disables
the IO APIC.
max_loop= [LOOP] Maximum number of loopback devices that can
be mounted
Format: <1-256>
mcatest= [IA-64]
mce [X86-32] Machine Check Exception
mce=option [X86-64] See Documentation/x86/x86_64/boot-options.txt
md= [HW] RAID subsystems devices and level
See Documentation/md.txt.
mdacon= [MDA]
Format: <first>,<last>
Specifies range of consoles to be captured by the MDA.
mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
Amount of memory to be used when the kernel is not able
to see the whole system memory or for test.
[X86-32] Use together with memmap= to avoid physical
address space collisions. Without memmap= PCI devices
could be placed at addresses belonging to unused RAM.
mem=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel
memory.
memchunk=nn[KMG]
[KNL,SH] Allow user to override the default size for
per-device physically contiguous DMA buffers.
memmap=exactmap [KNL,X86] Enable setting of an exact
E820 memory map, as specified by the user.
Such memmap=exactmap lines can be constructed based on
BIOS output or other requirements. See the memmap=nn@ss
option description.
memmap=nn[KMG]@ss[KMG]
[KNL] Force usage of a specific region of memory
Region of memory to be used, from ss to ss+nn.
memmap=nn[KMG]#ss[KMG]
[KNL,ACPI] Mark specific memory as ACPI data.
Region of memory to be used, from ss to ss+nn.
memmap=nn[KMG]$ss[KMG]
[KNL,ACPI] Mark specific memory as reserved.
Region of memory to be used, from ss to ss+nn.
Example: Exclude memory from 0x18690000-0x1869ffff
memmap=64K$0x18690000
or
memmap=0x10000$0x18690000
memory_corruption_check=0/1 [X86]
Some BIOSes seem to corrupt the first 64k of
memory when doing things like suspend/resume.
Setting this option will scan the memory
looking for corruption. Enabling this will
both detect corruption and prevent the kernel
from using the memory being corrupted.
However, its intended as a diagnostic tool; if
repeatable BIOS-originated corruption always
affects the same memory, you can use memmap=
to prevent the kernel from using that memory.
memory_corruption_check_size=size [X86]
By default it checks for corruption in the low
64k, making this memory unavailable for normal
use. Use this parameter to scan for
corruption in more or less memory.
memory_corruption_check_period=seconds [X86]
By default it checks for corruption every 60
seconds. Use this parameter to check at some
other rate. 0 disables periodic checking.
memtest= [KNL,X86] Enable memtest
Format: <integer>
default : 0 <disable>
Specifies the number of memtest passes to be
performed. Each pass selects another test
pattern from a given set of patterns. Memtest
fills the memory with this pattern, validates
memory contents and reserves bad memory
regions that are detected.
meye.*= [HW] Set MotionEye Camera parameters
See Documentation/video4linux/meye.txt.
mfgpt_irq= [IA-32] Specify the IRQ to use for the
Multi-Function General Purpose Timers on AMD Geode
platforms.
mfgptfix [X86-32] Fix MFGPT timers on AMD Geode platforms when
the BIOS has incorrectly applied a workaround. TinyBIOS
version 0.98 is known to be affected, 0.99 fixes the
problem by letting the user disable the workaround.
mga= [HW,DRM]
min_addr=nn[KMG] [KNL,BOOT,ia64] All physical memory below this
physical address is ignored.
mini2440= [ARM,HW,KNL]
Format:[0..2][b][c][t]
Default: "0tb"
MINI2440 configuration specification:
0 - The attached screen is the 3.5" TFT
1 - The attached screen is the 7" TFT
2 - The VGA Shield is attached (1024x768)
Leaving out the screen size parameter will not load
the TFT driver, and the framebuffer will be left
unconfigured.
b - Enable backlight. The TFT backlight pin will be
linked to the kernel VESA blanking code and a GPIO
LED. This parameter is not necessary when using the
VGA shield.
c - Enable the s3c camera interface.
t - Reserved for enabling touchscreen support. The
touchscreen support is not enabled in the mainstream
kernel as of 2.6.30, a preliminary port can be found
in the "bleeding edge" mini2440 support kernel at
http://repo.or.cz/w/linux-2.6/mini2440.git
mminit_loglevel=
[KNL] When CONFIG_DEBUG_MEMORY_INIT is set, this
parameter allows control of the logging verbosity for
the additional memory initialisation checks. A value
of 0 disables mminit logging and a level of 4 will
log everything. Information is printed at KERN_DEBUG
so loglevel=8 may also need to be specified.
mousedev.tap_time=
[MOUSE] Maximum time between finger touching and
leaving touchpad surface for touch to be considered
a tap and be reported as a left button click (for
touchpads working in absolute mode only).
Format: <msecs>
mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices
reporting absolute coordinates, such as tablets
mousedev.yres= [MOUSE] Vertical screen resolution, used for devices
reporting absolute coordinates, such as tablets
movablecore=nn[KMG] [KNL,X86,IA-64,PPC] This parameter
is similar to kernelcore except it specifies the
amount of memory used for migratable allocations.
If both kernelcore and movablecore is specified,
then kernelcore will be at *least* the specified
value but may be more. If movablecore on its own
is specified, the administrator must be careful
that the amount of memory usable for all allocations
is not too small.
MTD_Partition= [MTD]
Format: <name>,<region-number>,<size>,<offset>
MTD_Region= [MTD] Format:
<name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
mtdparts= [MTD]
See drivers/mtd/cmdlinepart.c.
onenand.bdry= [HW,MTD] Flex-OneNAND Boundary Configuration
Format: [die0_boundary][,die0_lock][,die1_boundary][,die1_lock]
boundary - index of last SLC block on Flex-OneNAND.
The remaining blocks are configured as MLC blocks.
lock - Configure if Flex-OneNAND boundary should be locked.
Once locked, the boundary cannot be changed.
1 indicates lock status, 0 indicates unlock status.
mtdset= [ARM]
ARM/S3C2412 JIVE boot control
See arch/arm/mach-s3c2412/mach-jive.c
mtouchusb.raw_coordinates=
[HW] Make the MicroTouch USB driver use raw coordinates
('y', default) or cooked coordinates ('n')
mtrr_chunk_size=nn[KMG] [X86]
used for mtrr cleanup. It is largest continuous chunk
that could hold holes aka. UC entries.
mtrr_gran_size=nn[KMG] [X86]
Used for mtrr cleanup. It is granularity of mtrr block.
Default is 1.
Large value could prevent small alignment from
using up MTRRs.
mtrr_spare_reg_nr=n [X86]
Format: <integer>
Range: 0,7 : spare reg number
Default : 1
Used for mtrr cleanup. It is spare mtrr entries number.
Set to 2 or more if your graphical card needs more.
n2= [NET] SDL Inc. RISCom/N2 synchronous serial card
netdev= [NET] Network devices parameters
Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
Note that mem_start is often overloaded to mean
something different and driver-specific.
This usage is only documented in each driver source
file if at all.
nf_conntrack.acct=
[NETFILTER] Enable connection tracking flow accounting
0 to disable accounting
1 to enable accounting
Default value is 0.
nfsaddrs= [NFS]
See Documentation/filesystems/nfs/nfsroot.txt.
nfsroot= [NFS] nfs root filesystem for disk-less boxes.
See Documentation/filesystems/nfs/nfsroot.txt.
nfs.callback_tcpport=
[NFS] set the TCP port on which the NFSv4 callback
channel should listen.
nfs.cache_getent=
[NFS] sets the pathname to the program which is used
to update the NFS client cache entries.
nfs.cache_getent_timeout=
[NFS] sets the timeout after which an attempt to
update a cache entry is deemed to have failed.
nfs.idmap_cache_timeout=
[NFS] set the maximum lifetime for idmapper cache
entries.
nfs.enable_ino64=
[NFS] enable 64-bit inode numbers.
If zero, the NFS client will fake up a 32-bit inode
number for the readdir() and stat() syscalls instead
of returning the full 64-bit number.
The default is to return 64-bit inode numbers.
nmi_debug= [KNL,AVR32,SH] Specify one or more actions to take
when a NMI is triggered.
Format: [state][,regs][,debounce][,die]
nmi_watchdog= [KNL,BUGS=X86] Debugging features for SMP kernels
Format: [panic,][num]
Valid num: 0,1,2
0 - turn nmi_watchdog off
1 - use the IO-APIC timer for the NMI watchdog
2 - use the local APIC for the NMI watchdog using
a performance counter. Note: This will use one
performance counter and the local APIC's performance
vector.
When panic is specified, panic when an NMI watchdog
timeout occurs.
This is useful when you use a panic=... timeout and
need the box quickly up again.
Instead of 1 and 2 it is possible to use the following
symbolic names: lapic and ioapic
Example: nmi_watchdog=2 or nmi_watchdog=panic,lapic
netpoll.carrier_timeout=
[NET] Specifies amount of time (in seconds) that
netpoll should wait for a carrier. By default netpoll
waits 4 seconds.
no387 [BUGS=X86-32] Tells the kernel to use the 387 maths
emulation library even if a 387 maths coprocessor
is present.
no_console_suspend
[HW] Never suspend the console
Disable suspending of consoles during suspend and
hibernate operations. Once disabled, debugging
messages can reach various consoles while the rest
of the system is being put to sleep (ie, while
debugging driver suspend/resume hooks). This may
not work reliably with all consoles, but is known
to work with serial and VGA consoles.
noaliencache [MM, NUMA, SLAB] Disables the allocation of alien
caches in the slab allocator. Saves per-node memory,
but will impact performance.
noalign [KNL,ARM]
noapic [SMP,APIC] Tells the kernel to not make use of any
IOAPICs that may be present in the system.
nobats [PPC] Do not use BATs for mapping kernel lowmem
on "Classic" PPC cores.
nocache [ARM]
noclflush [BUGS=X86] Don't use the CLFLUSH instruction
nodelayacct [KNL] Disable per-task delay accounting
nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects.
nodsp [SH] Disable hardware DSP at boot time.
noefi [X86] Disable EFI runtime services support.
noexec [IA-64]
noexec [X86]
On X86-32 available only on PAE configured kernels.
noexec=on: enable non-executable mappings (default)
noexec=off: disable non-executable mappings
noexec32 [X86-64]
This affects only 32-bit executables.
noexec32=on: enable non-executable mappings (default)
read doesn't imply executable mappings
noexec32=off: disable non-executable mappings
read implies executable mappings
nofpu [SH] Disable hardware FPU at boot time.
nofxsr [BUGS=X86-32] Disables x86 floating point extended
register save and restore. The kernel will only save
legacy floating-point registers on task switch.
noxsave [BUGS=X86] Disables x86 extended register state save
and restore using xsave. The kernel will fallback to
enabling legacy floating-point and sse state.
nohlt [BUGS=ARM,SH] Tells the kernel that the sleep(SH) or
wfi(ARM) instruction doesn't work correctly and not to
use it. This is also useful when using JTAG debugger.
no-hlt [BUGS=X86-32] Tells the kernel that the hlt
instruction doesn't work correctly and not to
use it.
file capabilities: add no_file_caps switch (v4) Add a no_file_caps boot option when file capabilities are compiled into the kernel (CONFIG_SECURITY_FILE_CAPABILITIES=y). This allows distributions to ship a kernel with file capabilities compiled in, without forcing users to use (and understand and trust) them. When no_file_caps is specified at boot, then when a process executes a file, any file capabilities stored with that file will not be used in the calculation of the process' new capability sets. This means that booting with the no_file_caps boot option will not be the same as booting a kernel with file capabilities compiled out - in particular a task with CAP_SETPCAP will not have any chance of passing capabilities to another task (which isn't "really" possible anyway, and which may soon by killed altogether by David Howells in any case), and it will instead be able to put new capabilities in its pI. However since fI will always be empty and pI is masked with fI, it gains the task nothing. We also support the extra prctl options, setting securebits and dropping capabilities from the per-process bounding set. The other remaining difference is that killpriv, task_setscheduler, setioprio, and setnice will continue to be hooked. That will be noticable in the case where a root task changed its uid while keeping some caps, and another task owned by the new uid tries to change settings for the more privileged task. Changelog: Nov 05 2008: (v4) trivial port on top of always-start-\ with-clear-caps patch Sep 23 2008: nixed file_caps_enabled when file caps are not compiled in as it isn't used. Document no_file_caps in kernel-parameters.txt. Signed-off-by: Serge Hallyn <serue@us.ibm.com> Acked-by: Andrew G. Morgan <morgan@kernel.org> Signed-off-by: James Morris <jmorris@namei.org>
2008-11-05 22:08:52 +00:00
no_file_caps Tells the kernel not to honor file capabilities. The
only way then for a file to be executed with privilege
is to be setuid root or executed by root.
nohalt [IA-64] Tells the kernel not to use the power saving
function PAL_HALT_LIGHT when idle. This increases
power-consumption. On the positive side, it reduces
interrupt wake-up latency, which may improve performance
in certain environments such as networked servers or
real-time systems.
nohz= [KNL] Boottime enable/disable dynamic ticks
Valid arguments: on, off
Default: on
noiotrap [SH] Disables trapped I/O port accesses.
noirqdebug [X86-32] Disables the code which attempts to detect and
disable unhandled interrupt sources.
no_timer_check [X86,APIC] Disables the code which tests for
broken timer IRQ sources.
noisapnp [ISAPNP] Disables ISA PnP code.
noinitrd [RAM] Tells the kernel not to load any configured
initial RAM disk.
nointremap [X86-64, Intel-IOMMU] Do not enable interrupt
remapping.
[Deprecated - use intremap=off]
nointroute [IA-64]
nojitter [IA64] Disables jitter checking for ITC timers.
nolapic [X86-32,APIC] Do not enable or use the local APIC.
nolapic_timer [X86-32,APIC] Do not use the local APIC timer.
noltlbs [PPC] Do not use large page/tlb entries for kernel
lowmem mapping on PPC40x.
nomca [IA-64] Disable machine check abort handling
nomce [X86-32] Machine Check Exception
nomfgpt [X86-32] Disable Multi-Function General Purpose
Timer usage (for AMD Geode machines).
nopat [X86] Disable PAT (page attribute table extension of
pagetables) support.
norandmaps Don't use address space randomization. Equivalent to
echo 0 > /proc/sys/kernel/randomize_va_space
noreplace-paravirt [X86-32,PV_OPS] Don't patch paravirt_ops
noreplace-smp [X86-32,SMP] Don't replace SMP instructions
with UP alternatives
noresidual [PPC] Don't use residual data on PReP machines.
noresume [SWSUSP] Disables resume and restores original swap
space.
no-scroll [VGA] Disables scrollback.
This is required for the Braillex ib80-piezo Braille
reader made by F.H. Papenmeier (Germany).
nosbagart [IA-64]
nosep [BUGS=X86-32] Disables x86 SYSENTER/SYSEXIT support.
nosmp [SMP] Tells an SMP kernel to act as a UP kernel,
and disable the IO APIC. legacy for "maxcpus=0".
nosoftlockup [KNL] Disable the soft-lockup detector.
noswapaccount [KNL] Disable accounting of swap in memory resource
controller. (See Documentation/cgroups/memory.txt)
nosync [HW,M68K] Disables sync negotiation for all devices.
notsc [BUGS=X86-32] Disable Time Stamp Counter
nousb [USB] Disable the USB subsystem
lockup_detector: Combine nmi_watchdog and softlockup detector The new nmi_watchdog (which uses the perf event subsystem) is very similar in structure to the softlockup detector. Using Ingo's suggestion, I combined the two functionalities into one file: kernel/watchdog.c. Now both the nmi_watchdog (or hardlockup detector) and softlockup detector sit on top of the perf event subsystem, which is run every 60 seconds or so to see if there are any lockups. To detect hardlockups, cpus not responding to interrupts, I implemented an hrtimer that runs 5 times for every perf event overflow event. If that stops counting on a cpu, then the cpu is most likely in trouble. To detect softlockups, tasks not yielding to the scheduler, I used the previous kthread idea that now gets kicked every time the hrtimer fires. If the kthread isn't being scheduled neither is anyone else and the warning is printed to the console. I tested this on x86_64 and both the softlockup and hardlockup paths work. V2: - cleaned up the Kconfig and softlockup combination - surrounded hardlockup cases with #ifdef CONFIG_PERF_EVENTS_NMI - seperated out the softlockup case from perf event subsystem - re-arranged the enabling/disabling nmi watchdog from proc space - added cpumasks for hardlockup failure cases - removed fallback to soft events if no PMU exists for hard events V3: - comment cleanups - drop support for older softlockup code - per_cpu cleanups - completely remove software clock base hardlockup detector - use per_cpu masking on hard/soft lockup detection - #ifdef cleanups - rename config option NMI_WATCHDOG to LOCKUP_DETECTOR - documentation additions V4: - documentation fixes - convert per_cpu to __get_cpu_var - powerpc compile fixes V5: - split apart warn flags for hard and soft lockups TODO: - figure out how to make an arch-agnostic clock2cycles call (if possible) to feed into perf events as a sample period [fweisbec: merged conflict patch] Signed-off-by: Don Zickus <dzickus@redhat.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Cyrill Gorcunov <gorcunov@gmail.com> Cc: Eric Paris <eparis@redhat.com> Cc: Randy Dunlap <randy.dunlap@oracle.com> LKML-Reference: <1273266711-18706-2-git-send-email-dzickus@redhat.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2010-05-07 21:11:44 +00:00
nowatchdog [KNL] Disable the lockup detector.
nowb [ARM]
nox2apic [X86-64,APIC] Do not enable x2APIC mode.
nptcg= [IA64] Override max number of concurrent global TLB
purges which is reported from either PAL_VM_SUMMARY or
SAL PALO.
nr_cpus= [SMP] Maximum number of processors that an SMP kernel
could support. nr_cpus=n : n >= 1 limits the kernel to
supporting 'n' processors. Later in runtime you can not
use hotplug cpu feature to put more cpu back to online.
just like you compile the kernel NR_CPUS=n
nr_uarts= [SERIAL] maximum number of UARTs to be registered.
change zonelist order: zonelist order selection logic Make zonelist creation policy selectable from sysctl/boot option v6. This patch makes NUMA's zonelist (of pgdat) order selectable. Available order are Default(automatic)/ Node-based / Zone-based. [Default Order] The kernel selects Node-based or Zone-based order automatically. [Node-based Order] This policy treats the locality of memory as the most important parameter. Zonelist order is created by each zone's locality. This means lower zones (ex. ZONE_DMA) can be used before higher zone (ex. ZONE_NORMAL) exhausion. IOW. ZONE_DMA will be in the middle of zonelist. current 2.6.21 kernel uses this. Pros. * A user can expect local memory as much as possible. Cons. * lower zone will be exhansted before higher zone. This may cause OOM_KILL. Maybe suitable if ZONE_DMA is relatively big and you never see OOM_KILL because of ZONE_DMA exhaution and you need the best locality. (example) assume 2 node NUMA. node(0) has ZONE_DMA/ZONE_NORMAL, node(1) has ZONE_NORMAL. *node(0)'s memory allocation order: node(0)'s NORMAL -> node(0)'s DMA -> node(1)'s NORMAL. *node(1)'s memory allocation order: node(1)'s NORMAL -> node(0)'s NORMAL -> node(0)'s DMA. [Zone-based order] This policy treats the zone type as the most important parameter. Zonelist order is created by zone-type order. This means lower zone never be used bofere higher zone exhaustion. IOW. ZONE_DMA will be always at the tail of zonelist. Pros. * OOM_KILL(bacause of lower zone) occurs only if the whole zones are exhausted. Cons. * memory locality may not be best. (example) assume 2 node NUMA. node(0) has ZONE_DMA/ZONE_NORMAL, node(1) has ZONE_NORMAL. *node(0)'s memory allocation order: node(0)'s NORMAL -> node(1)'s NORMAL -> node(0)'s DMA. *node(1)'s memory allocation order: node(1)'s NORMAL -> node(0)'s NORMAL -> node(0)'s DMA. bootoption "numa_zonelist_order=" and proc/sysctl is supporetd. command: %echo N > /proc/sys/vm/numa_zonelist_order Will rebuild zonelist in Node-based order. command: %echo Z > /proc/sys/vm/numa_zonelist_order Will rebuild zonelist in Zone-based order. Thanks to Lee Schermerhorn, he gives me much help and codes. [Lee.Schermerhorn@hp.com: add check_highest_zone to build_zonelists_in_zone_order] [akpm@linux-foundation.org: build fix] Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Lee Schermerhorn <lee.schermerhorn@hp.com> Cc: Christoph Lameter <clameter@sgi.com> Cc: Andi Kleen <ak@suse.de> Cc: "jesse.barnes@intel.com" <jesse.barnes@intel.com> Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-16 06:38:01 +00:00
numa_zonelist_order= [KNL, BOOT] Select zonelist order for NUMA.
one of ['zone', 'node', 'default'] can be specified
This can be set from sysctl after boot.
See Documentation/sysctl/vm.txt for details.
ohci1394_dma=early [HW] enable debugging via the ohci1394 driver.
See Documentation/debugging-via-ohci1394.txt for more
info.
olpc_ec_timeout= [OLPC] ms delay when issuing EC commands
Rather than timing out after 20 ms if an EC
command is not properly ACKed, override the length
of the timeout. We have interrupts disabled while
waiting for the ACK, so if this is set too high
interrupts *may* be lost!
omap_mux= [OMAP] Override bootloader pin multiplexing.
Format: <mux_mode0.mode_name=value>...
For example, to override I2C bus2:
omap_mux=i2c2_scl.i2c2_scl=0x100,i2c2_sda.i2c2_sda=0x100
oprofile.timer= [HW]
Use timer interrupt instead of performance counters
oprofile.cpu_type= Force an oprofile cpu type
This might be useful if you have an older oprofile
userland or if you want common events.
Format: { arch_perfmon }
arch_perfmon: [X86] Force use of architectural
perfmon on Intel CPUs instead of the
CPU specific event set.
OSS [HW,OSS]
See Documentation/sound/oss/oss-parameters.txt
panic= [KNL] Kernel behaviour on panic
Format: <timeout>
parkbd.port= [HW] Parallel port number the keyboard adapter is
connected to, default is 0.
Format: <parport#>
parkbd.mode= [HW] Parallel port keyboard adapter mode of operation,
0 for XT, 1 for AT (default is AT).
Format: <mode>
parport= [HW,PPT] Specify parallel ports. 0 disables.
Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
Use 'auto' to force the driver to use any
IRQ/DMA settings detected (the default is to
ignore detected IRQ/DMA settings because of
possible conflicts). You can specify the base
address, IRQ, and DMA settings; IRQ and DMA
should be numbers, or 'auto' (for using detected
settings on that particular port), or 'nofifo'
(to avoid using a FIFO even if it is detected).
Parallel ports are assigned in the order they
are specified on the command line, starting
with parport0.
parport_init_mode= [HW,PPT]
Configure VIA parallel port to operate in
a specific mode. This is necessary on Pegasos
computer where firmware has no options for setting
up parallel port mode and sets it to spp.
Currently this function knows 686a and 8231 chips.
Format: [spp|ps2|epp|ecp|ecpepp]
pause_on_oops=
Halt all CPUs after the first oops has been printed for
the specified number of seconds. This is to be used if
your oopses keep scrolling off the screen.
pcbit= [HW,ISDN]
pcd. [PARIDE]
See header of drivers/block/paride/pcd.c.
See also Documentation/blockdev/paride.txt.
pci=option[,option...] [PCI] various PCI subsystem options:
earlydump [X86] dump PCI config space before the kernel
changes anything
off [X86] don't probe for the PCI bus
bios [X86-32] force use of PCI BIOS, don't access
the hardware directly. Use this if your machine
has a non-standard PCI host bridge.
nobios [X86-32] disallow use of PCI BIOS, only direct
hardware access methods are allowed. Use this
if you experience crashes upon bootup and you
suspect they are caused by the BIOS.
conf1 [X86] Force use of PCI Configuration
Mechanism 1.
conf2 [X86] Force use of PCI Configuration
Mechanism 2.
noaer [PCIE] If the PCIEAER kernel config parameter is
enabled, this kernel boot option can be used to
disable the use of PCIE advanced error reporting.
nodomains [PCI] Disable support for multiple PCI
root domains (aka PCI segments, in ACPI-speak).
nommconf [X86] Disable use of MMCONFIG for PCI
Configuration
check_enable_amd_mmconf [X86] check for and enable
properly configured MMIO access to PCI
config space on AMD family 10h CPU
nomsi [MSI] If the PCI_MSI kernel config parameter is
enabled, this kernel boot option can be used to
disable the use of MSI interrupts system-wide.
noioapicquirk [APIC] Disable all boot interrupt quirks.
Safety option to keep boot IRQs enabled. This
should never be necessary.
ioapicreroute [APIC] Enable rerouting of boot IRQs to the
primary IO-APIC for bridges that cannot disable
boot IRQs. This fixes a source of spurious IRQs
when the system masks IRQs.
noioapicreroute [APIC] Disable workaround that uses the
boot IRQ equivalent of an IRQ that connects to
a chipset where boot IRQs cannot be disabled.
The opposite of ioapicreroute.
biosirq [X86-32] Use PCI BIOS calls to get the interrupt
routing table. These calls are known to be buggy
on several machines and they hang the machine
when used, but on other computers it's the only
way to get the interrupt routing table. Try
this option if the kernel is unable to allocate
IRQs or discover secondary PCI buses on your
motherboard.
rom [X86] Assign address space to expansion ROMs.
Use with caution as certain devices share
address decoders between ROMs and other
resources.
norom [X86] Do not assign address space to
PCI: boot parameter to avoid expansion ROM memory allocation Contention for scarce PCI memory resources has been growing due to an increasing number of PCI slots in large multi-node systems. The kernel currently attempts by default to allocate memory for all PCI expansion ROMs so there has also been an increasing number of PCI memory allocation failures seen on these systems. This occurs because the BIOS either (1) provides insufficient PCI memory resource for all the expansion ROMs or (2) provides adequate PCI memory resource for expansion ROMs but provides the space in kernel unexpected BIOS assigned P2P non-prefetch windows. The resulting PCI memory allocation failures may be benign when related to memory requests for expansion ROMs themselves but in some cases they can occur when attempting to allocate space for more critical BARs. This can happen when a successful expansion ROM allocation request consumes memory resource that was intended for a non-ROM BAR. We have seen this happen during PCI hotplug of an adapter that contains a P2P bridge where successful memory allocation for an expansion ROM BAR on device behind the bridge consumed memory that was intended for a non-ROM BAR on the P2P bridge. In all cases the allocation failure messages can be very confusing for users. This patch provides a new 'pci=norom' kernel boot parameter that can be used to disable the default PCI expansion ROM memory resource allocation. This provides a way to avoid the above described issues on systems that do not contain PCI devices for which drivers or user-level applications depend on the default PCI expansion ROM memory resource allocation behavior. Signed-off-by: Gary Hade <garyhade@us.ibm.com> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2008-05-12 20:57:46 +00:00
expansion ROMs that do not already have
BIOS assigned address ranges.
nobar [X86] Do not assign address space to the
BARs that weren't assigned by the BIOS.
irqmask=0xMMMM [X86] Set a bit mask of IRQs allowed to be
assigned automatically to PCI devices. You can
make the kernel exclude IRQs of your ISA cards
this way.
pirqaddr=0xAAAAA [X86] Specify the physical address
of the PIRQ table (normally generated
by the BIOS) if it is outside the
F0000h-100000h range.
lastbus=N [X86] Scan all buses thru bus #N. Can be
useful if the kernel is unable to find your
secondary buses and you want to tell it
explicitly which ones they are.
assign-busses [X86] Always assign all PCI bus
numbers ourselves, overriding
whatever the firmware may have done.
usepirqmask [X86] Honor the possible IRQ mask stored
in the BIOS $PIR table. This is needed on
some systems with broken BIOSes, notably
some HP Pavilion N5400 and Omnibook XE3
notebooks. This will have no effect if ACPI
IRQ routing is enabled.
noacpi [X86] Do not use ACPI for IRQ routing
or for PCI scanning.
use_crs [X86] Use PCI host bridge window information
from ACPI. On BIOSes from 2008 or later, this
is enabled by default. If you need to use this,
please report a bug.
nocrs [X86] Ignore PCI host bridge windows from ACPI.
If you need to use this, please report a bug.
routeirq Do IRQ routing for all PCI devices.
This is normally done in pci_enable_device(),
so this option is a temporary workaround
for broken drivers that don't call it.
skip_isa_align [X86] do not align io start addr, so can
handle more pci cards
firmware [ARM] Do not re-enumerate the bus but instead
just use the configuration from the
bootloader. This is currently used on
IXP2000 systems where the bus has to be
configured a certain way for adjunct CPUs.
noearly [X86] Don't do any early type 1 scanning.
This might help on some broken boards which
machine check when some devices' config space
is read. But various workarounds are disabled
and some IOMMU drivers will not work.
PCI: optionally sort device lists breadth-first Problem: New Dell PowerEdge servers have 2 embedded ethernet ports, which are labeled NIC1 and NIC2 on the chassis, in the BIOS setup screens, and in the printed documentation. Assuming no other add-in ethernet ports in the system, Linux 2.4 kernels name these eth0 and eth1 respectively. Many people have come to expect this naming. Linux 2.6 kernels name these eth1 and eth0 respectively (backwards from expectations). I also have reports that various Sun and HP servers have similar behavior. Root cause: Linux 2.4 kernels walk the pci_devices list, which happens to be sorted in breadth-first order (or pcbios_find_device order on i386, which most often is breadth-first also). 2.6 kernels have both the pci_devices list and the pci_bus_type.klist_devices list, the latter is what is walked at driver load time to match the pci_id tables; this klist happens to be in depth-first order. On systems where, for physical routing reasons, NIC1 appears on a lower bus number than NIC2, but NIC2's bridge is discovered first in the depth-first ordering, NIC2 will be discovered before NIC1. If the list were sorted breadth-first, NIC1 would be discovered before NIC2. A PowerEdge 1955 system has the following topology which easily exhibits the difference between depth-first and breadth-first device lists. -[0000:00]-+-00.0 Intel Corporation 5000P Chipset Memory Controller Hub +-02.0-[0000:03-08]--+-00.0-[0000:04-07]--+-00.0-[0000:05-06]----00.0-[0000:06]----00.0 Broadcom Corporation NetXtreme II BCM5708S Gigabit Ethernet (labeled NIC2, 2.4 kernel name eth1, 2.6 kernel name eth0) +-1c.0-[0000:01-02]----00.0-[0000:02]----00.0 Broadcom Corporation NetXtreme II BCM5708S Gigabit Ethernet (labeled NIC1, 2.4 kernel name eth0, 2.6 kernel name eth1) Other factors, such as device driver load order and the presence of PCI slots at various points in the bus hierarchy further complicate this problem; I'm not trying to solve those here, just restore the device order, and thus basic behavior, that 2.4 kernels had. Solution: The solution can come in multiple steps. Suggested fix #1: kernel Patch below optionally sorts the two device lists into breadth-first ordering to maintain compatibility with 2.4 kernels. It adds two new command line options: pci=bfsort pci=nobfsort to force the sort order, or not, as you wish. It also adds DMI checks for the specific Dell systems which exhibit "backwards" ordering, to make them "right". Suggested fix #2: udev rules from userland Many people also have the expectation that embedded NICs are always discovered before add-in NICs (which this patch does not try to do). Using the PCI IRQ Routing Table provided by system BIOS, it's easy to determine which PCI devices are embedded, or if add-in, which PCI slot they're in. I'm working on a tool that would allow udev to name ethernet devices in ascending embedded, slot 1 .. slot N order, subsort by PCI bus/dev/fn breadth-first. It'll be possible to use it independent of udev as well for those distributions that don't use udev in their installers. Suggested fix #3: system board routing rules One can constrain the system board layout to put NIC1 ahead of NIC2 regardless of breadth-first or depth-first discovery order. This adds a significant level of complexity to board routing, and may not be possible in all instances (witness the above systems from several major manufacturers). I don't want to encourage this particular train of thought too far, at the expense of not doing #1 or #2 above. Feedback appreciated. Patch tested on a Dell PowerEdge 1955 blade with 2.6.18. You'll also note I took some liberty and temporarily break the klist abstraction to simplify and speed up the sort algorithm. I think that's both safe and appropriate in this instance. Signed-off-by: Matt Domsch <Matt_Domsch@dell.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-09-29 20:23:23 +00:00
bfsort Sort PCI devices into breadth-first order.
This sorting is done to get a device
order compatible with older (<= 2.4) kernels.
nobfsort Don't sort PCI devices into breadth-first order.
cbiosize=nn[KMG] The fixed amount of bus space which is
reserved for the CardBus bridge's IO window.
The default value is 256 bytes.
cbmemsize=nn[KMG] The fixed amount of bus space which is
reserved for the CardBus bridge's memory
window. The default value is 64 megabytes.
2009-03-16 08:13:39 +00:00
resource_alignment=
Format:
[<order of align>@][<domain>:]<bus>:<slot>.<func>[; ...]
Specifies alignment and device to reassign
aligned memory resources.
If <order of align> is not specified,
PAGE_SIZE is used as alignment.
PCI-PCI bridge can be specified, if resource
windows need to be expanded.
ecrc= Enable/disable PCIe ECRC (transaction layer
end-to-end CRC checking).
bios: Use BIOS/firmware settings. This is the
the default.
off: Turn ECRC off
on: Turn ECRC on.
PCI: optionally sort device lists breadth-first Problem: New Dell PowerEdge servers have 2 embedded ethernet ports, which are labeled NIC1 and NIC2 on the chassis, in the BIOS setup screens, and in the printed documentation. Assuming no other add-in ethernet ports in the system, Linux 2.4 kernels name these eth0 and eth1 respectively. Many people have come to expect this naming. Linux 2.6 kernels name these eth1 and eth0 respectively (backwards from expectations). I also have reports that various Sun and HP servers have similar behavior. Root cause: Linux 2.4 kernels walk the pci_devices list, which happens to be sorted in breadth-first order (or pcbios_find_device order on i386, which most often is breadth-first also). 2.6 kernels have both the pci_devices list and the pci_bus_type.klist_devices list, the latter is what is walked at driver load time to match the pci_id tables; this klist happens to be in depth-first order. On systems where, for physical routing reasons, NIC1 appears on a lower bus number than NIC2, but NIC2's bridge is discovered first in the depth-first ordering, NIC2 will be discovered before NIC1. If the list were sorted breadth-first, NIC1 would be discovered before NIC2. A PowerEdge 1955 system has the following topology which easily exhibits the difference between depth-first and breadth-first device lists. -[0000:00]-+-00.0 Intel Corporation 5000P Chipset Memory Controller Hub +-02.0-[0000:03-08]--+-00.0-[0000:04-07]--+-00.0-[0000:05-06]----00.0-[0000:06]----00.0 Broadcom Corporation NetXtreme II BCM5708S Gigabit Ethernet (labeled NIC2, 2.4 kernel name eth1, 2.6 kernel name eth0) +-1c.0-[0000:01-02]----00.0-[0000:02]----00.0 Broadcom Corporation NetXtreme II BCM5708S Gigabit Ethernet (labeled NIC1, 2.4 kernel name eth0, 2.6 kernel name eth1) Other factors, such as device driver load order and the presence of PCI slots at various points in the bus hierarchy further complicate this problem; I'm not trying to solve those here, just restore the device order, and thus basic behavior, that 2.4 kernels had. Solution: The solution can come in multiple steps. Suggested fix #1: kernel Patch below optionally sorts the two device lists into breadth-first ordering to maintain compatibility with 2.4 kernels. It adds two new command line options: pci=bfsort pci=nobfsort to force the sort order, or not, as you wish. It also adds DMI checks for the specific Dell systems which exhibit "backwards" ordering, to make them "right". Suggested fix #2: udev rules from userland Many people also have the expectation that embedded NICs are always discovered before add-in NICs (which this patch does not try to do). Using the PCI IRQ Routing Table provided by system BIOS, it's easy to determine which PCI devices are embedded, or if add-in, which PCI slot they're in. I'm working on a tool that would allow udev to name ethernet devices in ascending embedded, slot 1 .. slot N order, subsort by PCI bus/dev/fn breadth-first. It'll be possible to use it independent of udev as well for those distributions that don't use udev in their installers. Suggested fix #3: system board routing rules One can constrain the system board layout to put NIC1 ahead of NIC2 regardless of breadth-first or depth-first discovery order. This adds a significant level of complexity to board routing, and may not be possible in all instances (witness the above systems from several major manufacturers). I don't want to encourage this particular train of thought too far, at the expense of not doing #1 or #2 above. Feedback appreciated. Patch tested on a Dell PowerEdge 1955 blade with 2.6.18. You'll also note I took some liberty and temporarily break the klist abstraction to simplify and speed up the sort algorithm. I think that's both safe and appropriate in this instance. Signed-off-by: Matt Domsch <Matt_Domsch@dell.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-09-29 20:23:23 +00:00
pcie_aspm= [PCIE] Forcibly enable or disable PCIe Active State Power
Management.
off Disable ASPM.
force Enable ASPM even on devices that claim not to support it.
WARNING: Forcing ASPM on may cause system lockups.
pcie_pme= [PCIE,PM] Native PCIe PME signaling options:
Format: {auto|force}[,nomsi]
auto Use native PCIe PME signaling if the BIOS allows the
kernel to control PCIe config registers of root ports.
force Use native PCIe PME signaling even if the BIOS refuses
to allow the kernel to control the relevant PCIe config
registers.
nomsi Do not use MSI for native PCIe PME signaling (this makes
all PCIe root ports use INTx for everything).
pcmv= [HW,PCMCIA] BadgePAD 4
pd. [PARIDE]
See Documentation/blockdev/paride.txt.
pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
boot time.
Format: { 0 | 1 }
See arch/parisc/kernel/pdc_chassis.c
percpu_alloc= Select which percpu first chunk allocator to use.
Currently supported values are "embed" and "page".
Archs may support subset or none of the selections.
See comments in mm/percpu.c for details on each
allocator. This parameter is primarily for debugging
and performance comparison.
pf. [PARIDE]
See Documentation/blockdev/paride.txt.
pg. [PARIDE]
See Documentation/blockdev/paride.txt.
pirq= [SMP,APIC] Manual mp-table setup
See Documentation/x86/i386/IO-APIC.txt.
plip= [PPT,NET] Parallel port network link
Format: { parport<nr> | timid | 0 }
See also Documentation/parport.txt.
pmtmr= [X86] Manual setup of pmtmr I/O Port.
Override pmtimer IOPort with a hex value.
e.g. pmtmr=0x508
pnp.debug [PNP]
Enable PNP debug messages. This depends on the
CONFIG_PNP_DEBUG_MESSAGES option.
pnpacpi= [ACPI]
{ off }
pnpbios= [ISAPNP]
{ on | off | curr | res | no-curr | no-res }
pnp_reserve_irq=
[ISAPNP] Exclude IRQs for the autoconfiguration
pnp_reserve_dma=
[ISAPNP] Exclude DMAs for the autoconfiguration
pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
Ranges are in pairs (I/O port base and size).
pnp_reserve_mem=
[ISAPNP] Exclude memory regions for the
autoconfiguration.
Ranges are in pairs (memory base and size).
ports= [IP_VS_FTP] IPVS ftp helper module
Default is 21.
Up to 8 (IP_VS_APP_MAX_PORTS) ports
may be specified.
Format: <port>,<port>....
print-fatal-signals=
[KNL] debug: print fatal signals
If enabled, warn about various signal handling
related application anomalies: too many signals,
too many POSIX.1 timers, fatal signals causing a
coredump - etc.
If you hit the warning due to signal overflow,
you might want to try "ulimit -i unlimited".
default: off.
printk.time= Show timing data prefixed to each printk message line
Format: <bool> (1/Y/y=enable, 0/N/n=disable)
processor.max_cstate= [HW,ACPI]
Limit processor to maximum C-state
max_cstate=9 overrides any DMI blacklist limit.
processor.nocst [HW,ACPI]
Ignore the _CST method to determine C-states,
instead using the legacy FADT method
profile= [KNL] Enable kernel profiling via /proc/profile
Format: [schedule,]<number>
Param: "schedule" - profile schedule points.
Param: <number> - step/bucket size as a power of 2 for
statistical time based profiling.
Param: "sleep" - profile D-state sleeping (millisecs).
Requires CONFIG_SCHEDSTATS
Param: "kvm" - profile VM exits.
prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
before loading.
See Documentation/blockdev/ramdisk.txt.
psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
probe for; one of (bare|imps|exps|lifebook|any).
psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
per second.
psmouse.resetafter= [HW,MOUSE]
Try to reset the device after so many bad packets
(0 = never).
psmouse.resolution=
[HW,MOUSE] Set desired mouse resolution, in dpi.
psmouse.smartscroll=
[HW,MOUSE] Controls Logitech smartscroll autorepeat.
0 = disabled, 1 = enabled (default).
pt. [PARIDE]
See Documentation/blockdev/paride.txt.
pty.legacy_count=
[KNL] Number of legacy pty's. Overwrites compiled-in
default number.
quiet [KNL] Disable most log messages
r128= [HW,DRM]
raid= [HW,RAID]
See Documentation/md.txt.
ramdisk_blocksize= [RAM]
See Documentation/blockdev/ramdisk.txt.
ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
See Documentation/blockdev/ramdisk.txt.
rcupdate.blimit= [KNL,BOOT]
Set maximum number of finished RCU callbacks to process
in one batch.
rcupdate.qhimark= [KNL,BOOT]
Set threshold of queued
RCU callbacks over which batch limiting is disabled.
rcupdate.qlowmark= [KNL,BOOT]
Set threshold of queued RCU callbacks below which
batch limiting is re-enabled.
rdinit= [KNL]
Format: <full_path>
Run specified binary instead of /init from the ramdisk,
used for early userspace startup. See initrd.
reboot= [BUGS=X86-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
Format: <reboot_mode>[,<reboot_mode2>[,...]]
See arch/*/kernel/reboot.c or arch/*/kernel/process.c
relax_domain_level=
[KNL, SMP] Set scheduler's default relax_domain_level.
See Documentation/cgroups/cpusets.txt.
reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
reservetop= [X86-32]
Format: nn[KMG]
Reserves a hole at the top of the kernel virtual
address space.
reset_devices [KNL] Force drivers to reset the underlying device
during initialization.
resume= [SWSUSP]
Specify the partition device for software suspend
resume_offset= [SWSUSP]
Specify the offset from the beginning of the partition
given by "resume=" at which the swap header is located,
in <PAGE_SIZE> units (needed only for swap files).
See Documentation/power/swsusp-and-swap-files.txt
retain_initrd [RAM] Keep initrd memory after extraction
rhash_entries= [KNL,NET]
Set number of hash buckets for route cache
riscom8= [HW,SERIAL]
Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
ro [KNL] Mount root device read-only on boot
root= [KNL] Root filesystem
rootdelay= [KNL] Delay (in seconds) to pause before attempting to
mount the root filesystem
rootflags= [KNL] Set root filesystem mount option string
rootfstype= [KNL] Set root filesystem type
rootwait [KNL] Wait (indefinitely) for root device to show up.
Useful for devices that are detected asynchronously
(e.g. USB and MMC devices).
rw [KNL] Mount root device read-write on boot
S [KNL] Run init in single mode
sa1100ir [NET]
See drivers/net/irda/sa1100_ir.c.
sbni= [NET] Granch SBNI12 leased line adapter
sched_debug [KNL] Enables verbose scheduler debug messages.
security= [SECURITY] Choose a security module to enable at boot.
If this boot parameter is not specified, only the first
security module asking for security registration will be
loaded. An invalid security module name will be treated
as if no module has been chosen.
selinux= [SELINUX] Disable or enable SELinux at boot time.
Format: { "0" | "1" }
See security/selinux/Kconfig help text.
0 -- disable.
1 -- enable.
Default value is set via kernel config option.
If enabled at boot time, /selinux/disable can be used
later to disable prior to initial policy load.
apparmor= [APPARMOR] Disable or enable AppArmor at boot time
Format: { "0" | "1" }
See security/apparmor/Kconfig help text
0 -- disable.
1 -- enable.
Default value is set via kernel config option.
serialnumber [BUGS=X86-32]
shapers= [NET]
Maximal number of shapers.
show_msr= [x86] show boot-time MSR settings
Format: { <integer> }
Show boot-time (BIOS-initialized) MSR settings.
The parameter means the number of CPUs to show,
for example 1 means boot CPU only.
simeth= [IA-64]
simscsi=
slram= [HW,MTD]
slub_debug[=options[,slabs]] [MM, SLUB]
Enabling slub_debug allows one to determine the
culprit if slab objects become corrupted. Enabling
slub_debug can create guard zones around objects and
may poison objects when not in use. Also tracks the
last alloc / free. For more information see
Documentation/vm/slub.txt.
slub_max_order= [MM, SLUB]
Determines the maximum allowed order for slabs.
A high setting may cause OOMs due to memory
fragmentation. For more information see
Documentation/vm/slub.txt.
slub_min_objects= [MM, SLUB]
The minimum number of objects per slab. SLUB will
increase the slab order up to slub_max_order to
generate a sufficiently large slab able to contain
the number of objects indicated. The higher the number
of objects the smaller the overhead of tracking slabs
and the less frequently locks need to be acquired.
For more information see Documentation/vm/slub.txt.
slub_min_order= [MM, SLUB]
Determines the mininum page order for slabs. Must be
lower than slub_max_order.
For more information see Documentation/vm/slub.txt.
slub_nomerge [MM, SLUB]
Disable merging of slabs with similar size. May be
necessary if there is some reason to distinguish
allocs to different slabs. Debug options disable
merging on their own.
For more information see Documentation/vm/slub.txt.
smart2= [HW]
Format: <io1>[,<io2>[,...,<io8>]]
smp-alt-once [X86-32,SMP] On a hotplug CPU system, only
attempt to substitute SMP alternatives once at boot.
smsc-ircc2.nopnp [HW] Don't use PNP to discover SMC devices
smsc-ircc2.ircc_cfg= [HW] Device configuration I/O port
smsc-ircc2.ircc_sir= [HW] SIR base I/O port
smsc-ircc2.ircc_fir= [HW] FIR base I/O port
smsc-ircc2.ircc_irq= [HW] IRQ line
smsc-ircc2.ircc_dma= [HW] DMA channel
smsc-ircc2.ircc_transceiver= [HW] Transceiver type:
0: Toshiba Satellite 1800 (GP data pin select)
1: Fast pin select (default)
2: ATC IRMode
softlockup_panic=
[KNL] Should the soft-lockup detector generate panics.
sonypi.*= [HW] Sony Programmable I/O Control Device driver
See Documentation/sonypi.txt
specialix= [HW,SERIAL] Specialix multi-serial port adapter
See Documentation/serial/specialix.txt.
spia_io_base= [HW,MTD]
spia_fio_base=
spia_pedr=
spia_peddr=
stacktrace [FTRACE]
Enabled the stack tracer on boot up.
sti= [PARISC,HW]
Format: <num>
Set the STI (builtin display/keyboard on the HP-PARISC
machines) console (graphic card) which should be used
as the initial boot-console.
See also comment in drivers/video/console/sticore.c.
sti_font= [HW]
See comment in drivers/video/console/sticore.c.
stifb= [HW]
Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
sunrpc.min_resvport=
sunrpc.max_resvport=
[NFS,SUNRPC]
SunRPC servers often require that client requests
originate from a privileged port (i.e. a port in the
range 0 < portnr < 1024).
An administrator who wishes to reserve some of these
ports for other uses may adjust the range that the
kernel's sunrpc client considers to be privileged
using these two parameters to set the minimum and
maximum port values.
sunrpc.pool_mode=
[NFS]
Control how the NFS server code allocates CPUs to
service thread pools. Depending on how many NICs
you have and where their interrupts are bound, this
option will affect which CPUs will do NFS serving.
Note: this parameter cannot be changed while the
NFS server is running.
auto the server chooses an appropriate mode
automatically using heuristics
global a single global pool contains all CPUs
percpu one pool for each CPU
pernode one pool for each NUMA node (equivalent
to global on non-NUMA machines)
sunrpc.tcp_slot_table_entries=
sunrpc.udp_slot_table_entries=
[NFS,SUNRPC]
Sets the upper limit on the number of simultaneous
RPC calls that can be sent from the client to a
server. Increasing these values may allow you to
improve throughput, but will also increase the
amount of memory reserved for use by the client.
swiotlb= [IA-64] Number of I/O TLB slabs
switches= [HW,M68k]
sysrq_always_enabled
[KNL]
Ignore sysrq setting - this boot parameter will
neutralize any effect of /proc/sys/kernel/sysrq.
Useful for debugging.
tdfx= [HW,DRM]
test_suspend= [SUSPEND]
Specify "mem" (for Suspend-to-RAM) or "standby" (for
standby suspend) as the system sleep state to briefly
enter during system startup. The system is woken from
this state using a wakeup-capable RTC alarm.
thash_entries= [KNL,NET]
Set number of hash buckets for TCP connection
thermal.act= [HW,ACPI]
-1: disable all active trip points in all thermal zones
<degrees C>: override all lowest active trip points
thermal.crt= [HW,ACPI]
-1: disable all critical trip points in all thermal zones
<degrees C>: override all critical trip points
thermal.nocrt= [HW,ACPI]
Set to disable actions on ACPI thermal zone
critical and hot trip points.
thermal.off= [HW,ACPI]
1: disable ACPI thermal control
thermal.psv= [HW,ACPI]
-1: disable all passive trip points
<degrees C>: override all passive trip points to this
value
ACPI: thermal: expose "thermal.tzp=" to set global polling frequency Thermal Zone Polling frequency (_TZP) is an optional ACPI object recommending the rate that the OS should poll the associated thermal zone. If _TZP is 0, no polling should be used. If _TZP is non-zero, then the platform recommends that the OS poll the thermal zone at the specified rate. The minimum period is 30 seconds. The maximum period is 5 minutes. (note _TZP and thermal.tzp units are in deci-seconds, so _TZP = 300 corresponds to 30 seconds) If _TZP is not present, ACPI 3.0b recommends that the thermal zone be polled at an "OS provided default frequency". However, common industry practice is: 1. The BIOS never specifies any _TZP 2. High volume OS's from this century never poll any thermal zones Ie. The OS depends on the platform's ability to provoke thermal events when necessary, and the "OS provided default frequency" is "never":-) There is a proposal that ACPI 4.0 be updated to reflect common industry practice -- ie. no _TZP, no polling. The Linux kernel already follows this practice -- thermal zones are not polled unless _TZP is present and non-zero. But thermal zone polling is useful as a workaround for systems which have ACPI thermal control, but have an issue preventing thermal events. Indeed, some Linux distributions still set a non-zero thermal polling frequency for this reason. But rather than ask the user to write a polling frequency into all the /proc/acpi/thermal_zone/*/polling_frequency files, here we simply document and expose the already existing module parameter to do the same at system level, to simplify debugging those broken platforms. Note that thermal.tzp is a module-load time parameter only. Signed-off-by: Len Brown <len.brown@intel.com>
2007-08-12 04:12:26 +00:00
thermal.tzp= [HW,ACPI]
Specify global default ACPI thermal zone polling rate
<deci-seconds>: poll all this frequency
0: no polling (default)
topology= [S390]
Format: {off | on}
Specify if the kernel should make use of the cpu
topology informations if the hardware supports these.
The scheduler will make use of these informations and
e.g. base its process migration decisions on it.
Default is off.
tp720= [HW,PS2]
tpm_suspend_pcr=[HW,TPM]
Format: integer pcr id
Specify that at suspend time, the tpm driver
should extend the specified pcr with zeros,
as a workaround for some chips which fail to
flush the last written pcr on TPM_SaveState.
This will guarantee that all the other pcrs
are saved.
trace_buf_size=nn[KMG]
[FTRACE] will set tracing buffer size.
trace_event=[event-list]
[FTRACE] Set and start specified trace events in order
to facilitate early boot debugging.
See also Documentation/trace/events.txt
x86: Skip verification by the watchdog for TSC clocksource. Impact: Changes timekeeping on Vmware (or with tsc=reliable). This is achieved by resetting the CLOCKSOURCE_MUST_VERIFY flag. We add a tsc=reliable commandline option to enable this. This enables legacy hardware without HPET, LAPIC, or ACPI timers to enter high-resolution timer mode. Along with that have extended this to be used in virtualization environement too. Now we also set this flag if the X86_FEATURE_TSC_RELIABLE bit is set. This is important since there is a wrap-around problem with the acpi_pm timer. The acpi_pm counter is just 24bits and this can overflow in ~4 seconds. With the NO_HZ kernels in virtualized environment, there can be situations when the guest is descheduled for longer duration, as a result we may miss the wrap of the acpi counter. When TSC is used as a clocksource and acpi_pm timer is being used as the watchdog clocksource this error in acpi_pm results in TSC being marked as unstable, and essentially results in time dropping in chunks of 4 seconds whenever this wrap is missed. Since the virtualized TSC is reliable on VMware, we should always use the TSCs clocksource on VMware, so we skip the verfication at runtime, by checking for the feature bit. Since we reset the flag for mgeode systems too, i have combined the mgeode case with the feature bit check. Signed-off-by: Jeff Hansen <jhansen@cardaccess-inc.com> Signed-off-by: Alok N Kataria <akataria@vmware.com> Signed-off-by: Dan Hecht <dhecht@vmware.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2008-10-25 00:22:01 +00:00
tsc= Disable clocksource-must-verify flag for TSC.
Format: <string>
[x86] reliable: mark tsc clocksource as reliable, this
disables clocksource verification at runtime.
Used to enable high-resolution timer mode on older
hardware, and in virtualized environment.
turbografx.map[2|3]= [HW,JOY]
TurboGraFX parallel port interface
Format:
<port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
See also Documentation/input/joystick-parport.txt
uhash_entries= [KNL,NET]
Set number of hash buckets for UDP/UDP-Lite connections
uhci-hcd.ignore_oc=
[USB] Ignore overcurrent events (default N).
Some badly-designed motherboards generate lots of
bogus events, for ports that aren't wired to
anything. Set this parameter to avoid log spamming.
Note that genuine overcurrent events won't be
reported either.
unknown_nmi_panic
[X86]
Set unknown_nmi_panic=1 early on boot.
usbcore.autosuspend=
[USB] The autosuspend time delay (in seconds) used
for newly-detected USB devices (default 2). This
is the time required before an idle device will be
autosuspended. Devices for which the delay is set
to a negative value won't be autosuspended at all.
usbcore.usbfs_snoop=
[USB] Set to log all usbfs traffic (default 0 = off).
usbcore.blinkenlights=
[USB] Set to cycle leds on hubs (default 0 = off).
usbcore.old_scheme_first=
[USB] Start with the old device initialization
scheme (default 0 = off).
usbcore.use_both_schemes=
[USB] Try the other device initialization scheme
if the first one fails (default 1 = enabled).
usbcore.initial_descriptor_timeout=
[USB] Specifies timeout for the initial 64-byte
USB_REQ_GET_DESCRIPTOR request in milliseconds
(default 5000 = 5.0 seconds).
usbhid.mousepoll=
[USBHID] The interval which mice are to be polled at.
usb-storage.delay_use=
[UMS] The delay in seconds before a new device is
scanned for Logical Units (default 5).
usb-storage.quirks=
[UMS] A list of quirks entries to supplement or
override the built-in unusual_devs list. List
entries are separated by commas. Each entry has
the form VID:PID:Flags where VID and PID are Vendor
and Product ID values (4-digit hex numbers) and
Flags is a set of characters, each corresponding
to a common usb-storage quirk flag as follows:
a = SANE_SENSE (collect more than 18 bytes
of sense data);
b = BAD_SENSE (don't collect more than 18
bytes of sense data);
c = FIX_CAPACITY (decrease the reported
device capacity by one sector);
h = CAPACITY_HEURISTICS (decrease the
reported device capacity by one
sector if the number is odd);
i = IGNORE_DEVICE (don't bind to this
device);
l = NOT_LOCKABLE (don't try to lock and
unlock ejectable media);
m = MAX_SECTORS_64 (don't transfer more
than 64 sectors = 32 KB at a time);
o = CAPACITY_OK (accept the capacity
reported by the device);
r = IGNORE_RESIDUE (the device reports
bogus residue values);
s = SINGLE_LUN (the device has only one
Logical Unit);
w = NO_WP_DETECT (don't test whether the
medium is write-protected).
Example: quirks=0419:aaf5:rl,0421:0433:rc
x86, mm: Allow highmem user page tables to be disabled at boot time Distros generally (I looked at Debian, RHEL5 and SLES11) seem to enable CONFIG_HIGHPTE for any x86 configuration which has highmem enabled. This means that the overhead applies even to machines which have a fairly modest amount of high memory and which therefore do not really benefit from allocating PTEs in high memory but still pay the price of the additional mapping operations. Running kernbench on a 4G box I found that with CONFIG_HIGHPTE=y but no actual highptes being allocated there was a reduction in system time used from 59.737s to 55.9s. With CONFIG_HIGHPTE=y and highmem PTEs being allocated: Average Optimal load -j 4 Run (std deviation): Elapsed Time 175.396 (0.238914) User Time 515.983 (5.85019) System Time 59.737 (1.26727) Percent CPU 263.8 (71.6796) Context Switches 39989.7 (4672.64) Sleeps 42617.7 (246.307) With CONFIG_HIGHPTE=y but with no highmem PTEs being allocated: Average Optimal load -j 4 Run (std deviation): Elapsed Time 174.278 (0.831968) User Time 515.659 (6.07012) System Time 55.9 (1.07799) Percent CPU 263.8 (71.266) Context Switches 39929.6 (4485.13) Sleeps 42583.7 (373.039) This patch allows the user to control the allocation of PTEs in highmem from the command line ("userpte=nohigh") but retains the status-quo as the default. It is possible that some simple heuristic could be developed which allows auto-tuning of this option however I don't have a sufficiently large machine available to me to perform any particularly meaningful experiments. We could probably handwave up an argument for a threshold at 16G of total RAM. Assuming 768M of lowmem we have 196608 potential lowmem PTE pages. Each page can map 2M of RAM in a PAE-enabled configuration, meaning a maximum of 384G of RAM could potentially be mapped using lowmem PTEs. Even allowing generous factor of 10 to account for other required lowmem allocations, generous slop to account for page sharing (which reduces the total amount of RAM mappable by a given number of PT pages) and other innacuracies in the estimations it would seem that even a 32G machine would not have a particularly pressing need for highmem PTEs. I think 32G could be considered to be at the upper bound of what might be sensible on a 32 bit machine (although I think in practice 64G is still supported). It's seems questionable if HIGHPTE is even a win for any amount of RAM you would sensibly run a 32 bit kernel on rather than going 64 bit. Signed-off-by: Ian Campbell <ian.campbell@citrix.com> LKML-Reference: <1266403090-20162-1-git-send-email-ian.campbell@citrix.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2010-02-17 10:38:10 +00:00
userpte=
[X86] Flags controlling user PTE allocations.
nohigh = do not allocate PTE pages in
HIGHMEM regardless of setting
of CONFIG_HIGHPTE.
vdso= [X86,SH]
vdso=2: enable compat VDSO (default with COMPAT_VDSO)
[PATCH] vdso: randomize the i386 vDSO by moving it into a vma Move the i386 VDSO down into a vma and thus randomize it. Besides the security implications, this feature also helps debuggers, which can COW a vma-backed VDSO just like a normal DSO and can thus do single-stepping and other debugging features. It's good for hypervisors (Xen, VMWare) too, which typically live in the same high-mapped address space as the VDSO, hence whenever the VDSO is used, they get lots of guest pagefaults and have to fix such guest accesses up - which slows things down instead of speeding things up (the primary purpose of the VDSO). There's a new CONFIG_COMPAT_VDSO (default=y) option, which provides support for older glibcs that still rely on a prelinked high-mapped VDSO. Newer distributions (using glibc 2.3.3 or later) can turn this option off. Turning it off is also recommended for security reasons: attackers cannot use the predictable high-mapped VDSO page as syscall trampoline anymore. There is a new vdso=[0|1] boot option as well, and a runtime /proc/sys/vm/vdso_enabled sysctl switch, that allows the VDSO to be turned on/off. (This version of the VDSO-randomization patch also has working ELF coredumping, the previous patch crashed in the coredumping code.) This code is a combined work of the exec-shield VDSO randomization code and Gerd Hoffmann's hypervisor-centric VDSO patch. Rusty Russell started this patch and i completed it. [akpm@osdl.org: cleanups] [akpm@osdl.org: compile fix] [akpm@osdl.org: compile fix 2] [akpm@osdl.org: compile fix 3] [akpm@osdl.org: revernt MAXMEM change] Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Arjan van de Ven <arjan@infradead.org> Cc: Gerd Hoffmann <kraxel@suse.de> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Zachary Amsden <zach@vmware.com> Cc: Andi Kleen <ak@muc.de> Cc: Jan Beulich <jbeulich@novell.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-27 09:53:50 +00:00
vdso=1: enable VDSO (default)
vdso=0: disable VDSO mapping
vdso32= [X86]
vdso32=2: enable compat VDSO (default with COMPAT_VDSO)
vdso32=1: enable 32-bit VDSO (default)
vdso32=0: disable 32-bit VDSO mapping
vector= [IA-64,SMP]
vector=percpu: enable percpu vector domain
video= [FB] Frame buffer configuration
See Documentation/fb/modedb.txt.
vga= [BOOT,X86-32] Select a particular video mode
See Documentation/x86/boot.txt and
Documentation/svga.txt.
Use vga=ask for menu.
This is actually a boot loader parameter; the value is
passed to the kernel using a special protocol.
vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
size of <nn>. This can be used to increase the
minimum size (128MB on x86). It can also be used to
decrease the size and leave more room for directly
mapped kernel RAM.
vmhalt= [KNL,S390] Perform z/VM CP command after system halt.
Format: <command>
vmpanic= [KNL,S390] Perform z/VM CP command after kernel panic.
Format: <command>
vmpoff= [KNL,S390] Perform z/VM CP command after power off.
Format: <command>
vt.cur_default= [VT] Default cursor shape.
Format: 0xCCBBAA, where AA, BB, and CC are the same as
the parameters of the <Esc>[?A;B;Cc escape sequence;
see VGA-softcursor.txt. Default: 2 = underline.
vt.default_blu= [VT]
Format: <blue0>,<blue1>,<blue2>,...,<blue15>
Change the default blue palette of the console.
This is a 16-member array composed of values
ranging from 0-255.
vt.default_grn= [VT]
Format: <green0>,<green1>,<green2>,...,<green15>
Change the default green palette of the console.
This is a 16-member array composed of values
ranging from 0-255.
vt.default_red= [VT]
Format: <red0>,<red1>,<red2>,...,<red15>
Change the default red palette of the console.
This is a 16-member array composed of values
ranging from 0-255.
vt.default_utf8=
[VT]
Format=<0|1>
Set system-wide default UTF-8 mode for all tty's.
Default is 1, i.e. UTF-8 mode is enabled for all
newly opened terminals.
vt.global_cursor_default=
[VT]
Format=<-1|0|1>
Set system-wide default for whether a cursor
is shown on new VTs. Default is -1,
i.e. cursors will be created by default unless
overridden by individual drivers. 0 will hide
cursors, 1 will display them.
watchdog timers [HW,WDT] For information on watchdog timers,
see Documentation/watchdog/watchdog-parameters.txt
or other driver-specific files in the
Documentation/watchdog/ directory.
x2apic_phys [X86-64,APIC] Use x2apic physical mode instead of
default x2apic cluster mode on platforms
supporting x2apic.
x86_mrst_timer= [X86-32,APBT]
Choose timer option for x86 Moorestown MID platform.
Two valid options are apbt timer only and lapic timer
plus one apbt timer for broadcast timer.
x86_mrst_timer=apbt_only | lapic_and_apbt
xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks.
xd_geo= See header of drivers/block/xd.c.
xen_emul_unplug= [HW,X86,XEN]
Unplug Xen emulated devices
Format: [unplug0,][unplug1]
ide-disks -- unplug primary master IDE devices
aux-ide-disks -- unplug non-primary-master IDE devices
nics -- unplug network devices
all -- unplug all emulated devices (NICs and IDE disks)
unnecessary -- unplugging emulated devices is
unnecessary even if the host did not respond to
the unplug protocol
never -- do not unplug even if version check succeeds
xirc2ps_cs= [NET,PCMCIA]
Format:
<irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
______________________________________________________________________
TODO:
Add more DRM drivers.