Problem:
selwakeup required calling pfind which would cause lock order
reversals with the allproc_lock and the per-process filedesc lock.
Solution:
Instead of recording the pid of the select()'ing process into the
selinfo structure, actually record a pointer to the thread. To
avoid dereferencing a bad address all the selinfo structures that
are in use by a thread are kept in a list hung off the thread
(protected by sellock). When a selwakeup occurs the selinfo is
removed from that threads list, it is also removed on the way out
of select or poll where the thread will traverse its list removing
all the selinfos from its own list.
Problem:
Previously the PROC_LOCK was used to provide the mutual exclusion
needed to ensure proper locking, this couldn't work because there
was a single condvar used for select and poll and condvars can
only be used with a single mutex.
Solution:
Introduce a global mutex 'sellock' which is used to provide mutual
exclusion when recording events to wait on as well as performing
notification when an event occurs.
Interesting note:
schedlock is required to manipulate the per-thread TDF_SELECT
flag, however if given its own field it would not need schedlock,
also because TDF_SELECT is only manipulated under sellock one
doesn't actually use schedlock for syncronization, only to protect
against corruption.
Proc locks are no longer used in select/poll.
Portions contributed by: davidc
AIOGCAP ioctl reports software-emulated formats. It defaults to on. People
who use performance-sensitive audio software and do not want it to pick a
software-emulated audio format instead of one supported by their hardware
should turn it off.
This unbreaks isdnphone(1) on systems with PCM-only sound cards.
Approved by: cg
for success, non-zero otherwise. The maestro and maestro3 drivers were
returning the format code, which was being interpreted as a failure code.
Fixed. No one seems to have noticed that the maestro driver was broken,
but I'll fix it anyways.
MFC after: 2 weeks
* be more specific in verbose boot messages
* allow the feeder subsystem to veto pcm* attaching if there is an error
initialising the root feeder
* don't free/malloc a new tmpbuf when resizing a snd_dbuf to the same size as
it currently is
* store the feeder description in the feeder structure instead of mallocing
space for it
extensively as none of my testboxes have speakers or an audio source at
present, but the chains built look correct and reading /dev/audio (ulaw,
translated from signed 16 bit little-endian) gives values within the
expected range for silence.
default format for the chosen subdevice cannot be obtained return an error
instead of returning success with an indeteterminate format selected.
note that this should never happen once the feederchain builder works for
recording.
likely looking rate calculation.
Install interrupt handler before calling ich_init as the initialization
occasionally generates spurious interrupts.
These changes are derived from cg's work in progress version of this
driver.
hw.midi.debug and hw.midi.seq.debug to 1 to enable debug log.
- Make debug messages human-frendly.
- Implement /dev/music.
- Add a timer engine required by /dev/music.
- Fix nonblocking I/O.
- Fix the numbering of midi and synth devices.
- Move from msleep/wakeup to condvar.
- Return either zero or a positive errno value from a function.
Return additional result via references.
- Unify the typedef of callback functions.
must be cleared to prevent machine hanging (presently aflicts -current
and -stable).
Problem reported by Bruce Montague <brucem@cse.iitkgp.ernet.in>
PR: kern/29769 (probably)
- The MD functions critical_enter/exit are renamed to start with a cpu_
prefix.
- MI wrapper functions critical_enter/exit maintain a per-thread nesting
count and a per-thread critical section saved state set when entering
a critical section while at nesting level 0 and restored when exiting
to nesting level 0. This moves the saved state out of spin mutexes so
that interlocking spin mutexes works properly.
- Most low-level MD code that used critical_enter/exit now use
cpu_critical_enter/exit. MI code such as device drivers and spin
mutexes use the MI wrappers. Note that since the MI wrappers store
the state in the current thread, they do not have any return values or
arguments.
- mtx_intr_enable() is replaced with a constant CRITICAL_FORK which is
assigned to curthread->td_savecrit during fork_exit().
Tested on: i386, alpha
the link rate - some ich motherboards overclock ac97 out of the box.
Will hopefully replace this with a callibration loop in time for 4.5R
freeze.
Problem reported by Luigi Rizzo and fix derived from his code (put
diff in ich.c rather than ac97.c).
MFC after: 3 days
pcm0: ac97 codec failed to reset extended mode (0, got 80)
This was due to not masking off the correct extended function bits
in the read value from the extended status reg.
MFC after: 2 days
