linux/sound/core
Takashi Iwai 113ce08109 ALSA: pcm: Don't suspend stream in unrecoverable PCM state
Currently PCM core sets each opened stream forcibly to SUSPENDED state
via snd_pcm_suspend_all() call, and the user-space is responsible for
re-triggering the resume manually either via snd_pcm_resume() or
prepare call.  The scheme works fine usually, but there are corner
cases where the stream can't be resumed by that call: the streams
still in OPEN state before finishing hw_params.  When they are
suspended, user-space cannot perform resume or prepare because they
haven't been set up yet.  The only possible recovery is to re-open the
device, which isn't nice at all.  Similarly, when a stream is in
DISCONNECTED state, it makes no sense to change it to SUSPENDED
state.  Ditto for in SETUP state; which you can re-prepare directly.

So, this patch addresses these issues by filtering the PCM streams to
be suspended by checking the PCM state.  When a stream is in either
OPEN, SETUP or DISCONNECTED as well as already SUSPENDED, the suspend
action is skipped.

To be noted, this problem was originally reported for the PCM runtime
PM on HD-audio.  And, the runtime PM problem itself was already
addressed (although not intended) by the code refactoring commits
3d21ef0b49 ("ALSA: pcm: Suspend streams globally via device type PM
ops") and 17bc4815de ("ALSA: pci: Remove superfluous
snd_pcm_suspend*() calls").  These commits eliminated the
snd_pcm_suspend*() calls from the runtime PM suspend callback code
path, hence the racy OPEN state won't appear while runtime PM.
(FWIW, the race window is between snd_pcm_open_substream() and the
first power up in azx_pcm_open().)

Although the runtime PM issue was already "fixed", the same problem is
still present for the system PM, hence this patch is still needed.
And for stable trees, this patch alone should suffice for fixing the
runtime PM problem, too.

Reported-and-tested-by: Jon Hunter <jonathanh@nvidia.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
2019-03-25 16:36:30 +01:00
..
oss ALSA: pcm: Fix possible OOB access in PCM oss plugins 2019-03-22 16:27:03 +01:00
seq ALSA: seq: oss: Fix Spectre v1 vulnerability 2019-03-21 13:23:51 +01:00
compress_offload.c ALSA: compress: Remove superfluous snd_info_register() calls 2019-02-06 18:11:54 +01:00
control_compat.c ALSA: control: fix a redundant-copy issue 2018-05-13 09:27:57 +02:00
control.c ALSA: control: Consolidate helpers for adding and replacing ctl elements 2018-11-24 20:04:10 +01:00
ctljack.c ALSA: declare snd_kcontrol_new structures as const 2017-05-30 10:29:25 +02:00
device.c ALSA: core: Assure control device to be registered at last 2018-05-17 08:21:23 +02:00
hrtimer.c Merge branch 'for-next' into for-linus 2017-11-13 15:43:13 +01:00
hwdep_compat.c
hwdep.c Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2018-01-31 09:25:20 -08:00
info_oss.c ALSA: core: Follow standard EXPORT_SYMBOL() declarations 2017-06-16 16:19:16 +02:00
info.c ALSA: info: Move card id proc creation into info.c 2019-02-06 18:11:58 +01:00
init.c ALSA: info: Move card id proc creation into info.c 2019-02-06 18:11:58 +01:00
isadma.c ALSA: core: Follow standard EXPORT_SYMBOL() declarations 2017-06-16 16:19:16 +02:00
jack.c ALSA: fix kernel-doc build warning 2017-10-30 08:10:07 +01:00
Kconfig docs: Fix some broken references 2018-06-15 18:10:01 -03:00
Makefile License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
memalloc.c ALSA: core: Don't allow NULL device for memory allocation 2019-02-05 11:05:26 +01:00
memory.c ALSA: core: Follow standard EXPORT_SYMBOL() declarations 2017-06-16 16:19:16 +02:00
misc.c ALSA: core: Follow standard EXPORT_SYMBOL() declarations 2017-06-16 16:19:16 +02:00
pcm_compat.c treewide: kmalloc() -> kmalloc_array() 2018-06-12 16:19:22 -07:00
pcm_dmaengine.c ASoC: dmaengine_pcm: Add support for packed transfers 2016-04-27 17:34:11 +01:00
pcm_drm_eld.c ALSA: pcm: use helper function to refer parameter as read-only 2017-05-17 07:24:39 +02:00
pcm_iec958.c ALSA: pcm: Allow 32 bit sample format in IEC958 channel status helper 2016-04-06 14:33:38 -07:00
pcm_lib.c ALSA: pcm: Comment why read blocks when PCM is not running 2019-02-13 08:01:05 +01:00
pcm_local.h ALSA: pcm: Unify snd_pcm_group initialization 2019-01-21 16:39:35 +01:00
pcm_memory.c ALSA: pcm: Define snd_pcm_lib_preallocate_*() as returning void 2019-02-08 14:24:12 +01:00
pcm_misc.c ALSA: pcm: add SNDRV_PCM_FORMAT_{S,U}20 2017-11-29 09:26:33 +01:00
pcm_native.c ALSA: pcm: Don't suspend stream in unrecoverable PCM state 2019-03-25 16:36:30 +01:00
pcm_param_trace.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
pcm_timer.c ALSA: pcm: include pcm_local.h and remove some extraneous tabs 2017-05-30 18:04:47 +02:00
pcm_trace.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
pcm.c ALSA: pcm: Remove superfluous snd_info_register() calls 2019-02-06 18:11:54 +01:00
rawmidi_compat.c ALSA: rawmidi: Fix missing input substream checks in compat ioctls 2018-04-19 18:16:15 +02:00
rawmidi.c ALSA: rawmidi: Fix potential Spectre v1 vulnerability 2019-03-21 13:21:15 +01:00
seq_device.c ALSA: seq: Cancel pending autoload work at unbinding device 2017-09-12 12:41:20 +02:00
sgbuf.c ALSA: memalloc: Add non-cached buffer type 2018-08-28 13:56:47 +02:00
sound_oss.c ALSA: core: Follow standard EXPORT_SYMBOL() declarations 2017-06-16 16:19:16 +02:00
sound.c ALSA: core: Follow standard EXPORT_SYMBOL() declarations 2017-06-16 16:19:16 +02:00
timer_compat.c ALSA: timer: Remove kernel warning at compat ioctl error paths 2017-11-21 16:36:11 +01:00
timer.c ALSA: timer: catch invalid timer object creation 2018-07-22 10:42:41 +02:00
vmaster.c - Introduce arithmetic overflow test helper functions (Rasmus) 2018-06-06 17:27:14 -07:00