linux/drivers/pci/pcie/Kconfig
Rajat Jain b2103ccbb6 PCI/ASPM: Add support for L1 substates
Add support for ASPM L1 substates.  For details about L1 substates, see the
PCIe r3.1 spec, which includes the ECN below in secs 5.5 and 7.33.

Add macros for the 4 new L1 substates, and add a new ASPM "POWER_SUPERSAVE"
policy that can be used to enable L1 substates on a system if desired.  The
new policy is in a sense, a superset of the existing POWERSAVE policy.  The
4 policies are now:

  DEFAULT: Reads and uses whatever ASPM states BIOS enabled
  PERFORMANCE: Everything except L0 disabled.
  POWERSAVE: L0s and L1 enabled (but not L1 substates)
  POWER_SUPERSAVE: L0s + L1 + L1 substates also enabled

[bhelgaas: add PCIe r3.1 spec reference]
Link: https://pcisig.com/sites/default/files/specification_documents/ECN_L1_PM_Substates_with_CLKREQ_31_May_2013_Rev10a.pdf
Signed-off-by: Rajat Jain <rajatja@google.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2017-02-14 17:43:51 -06:00

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#
# PCI Express Port Bus Configuration
#
config PCIEPORTBUS
bool "PCI Express Port Bus support"
depends on PCI
help
This automatically enables PCI Express Port Bus support. Users can
choose Native Hot-Plug support, Advanced Error Reporting support,
Power Management Event support and Virtual Channel support to run
on PCI Express Ports (Root or Switch).
#
# Include service Kconfig here
#
config HOTPLUG_PCI_PCIE
bool "PCI Express Hotplug driver"
depends on HOTPLUG_PCI && PCIEPORTBUS
help
Say Y here if you have a motherboard that supports PCI Express Native
Hotplug
When in doubt, say N.
source "drivers/pci/pcie/aer/Kconfig"
#
# PCI Express ASPM
#
config PCIEASPM
bool "PCI Express ASPM control" if EXPERT
depends on PCI && PCIEPORTBUS
default y
help
This enables OS control over PCI Express ASPM (Active State
Power Management) and Clock Power Management. ASPM supports
state L0/L0s/L1.
ASPM is initially set up by the firmware. With this option enabled,
Linux can modify this state in order to disable ASPM on known-bad
hardware or configurations and enable it when known-safe.
ASPM can be disabled or enabled at runtime via
/sys/module/pcie_aspm/parameters/policy
When in doubt, say Y.
config PCIEASPM_DEBUG
bool "Debug PCI Express ASPM"
depends on PCIEASPM
default n
help
This enables PCI Express ASPM debug support. It will add per-device
interface to control ASPM.
choice
prompt "Default ASPM policy"
default PCIEASPM_DEFAULT
depends on PCIEASPM
config PCIEASPM_DEFAULT
bool "BIOS default"
depends on PCIEASPM
help
Use the BIOS defaults for PCI Express ASPM.
config PCIEASPM_POWERSAVE
bool "Powersave"
depends on PCIEASPM
help
Enable PCI Express ASPM L0s and L1 where possible, even if the
BIOS did not.
config PCIEASPM_POWER_SUPERSAVE
bool "Power Supersave"
depends on PCIEASPM
help
Same as PCIEASPM_POWERSAVE, except it also enables L1 substates where
possible. This would result in higher power savings while staying in L1
where the components support it.
config PCIEASPM_PERFORMANCE
bool "Performance"
depends on PCIEASPM
help
Disable PCI Express ASPM L0s and L1, even if the BIOS enabled them.
endchoice
config PCIE_PME
def_bool y
depends on PCIEPORTBUS && PM
config PCIE_DPC
bool "PCIe Downstream Port Containment support"
depends on PCIEPORTBUS
default n
help
This enables PCI Express Downstream Port Containment (DPC)
driver support. DPC events from Root and Downstream ports
will be handled by the DPC driver. If your system doesn't
have this capability or you do not want to use this feature,
it is safe to answer N.
config PCIE_PTM
bool "PCIe Precision Time Measurement support"
default n
depends on PCIEPORTBUS
help
This enables PCI Express Precision Time Measurement (PTM)
support.
This is only useful if you have devices that support PTM, but it
is safe to enable even if you don't.