On 5/13/2021 3:25 PM, Takashi Sakamoto wrote:
Hi,
On Thu, May 13, 2021 at 01:34:25PM +0200, Amadeusz Sławiński wrote:
I was checking some stuff relater to NO_PERIOD_WAKEUP and noticed that axfer
has support for using either --sched-model=irq or --sched-model=timer.
However from few quick tests it seems like it doesn't work?
$ aplay -l
**** List of PLAYBACK Hardware Devices ****
card 0: PCH [HDA Intel PCH], device 0: ALC283 Analog [ALC283 Analog]
Subdevices: 1/1
Subdevice #0: subdevice #0
When using --sched-model=irq it transfers data until I press Ctrl+C
$ axfer transfer playback --sched-model=irq -D hw:0,0 -r 48000 -c2 -f S16_LE
/dev/urandom
PLAYBACK: Format 'Signed 16 bit Little Endian', Rate 48000 Hz, Channels
'Stereo'
^CPLAYBACK: Expected 4611686018427387903frames, Actual 163960frames
Aborted by signal: Interrupt
However with --sched-model=timer it time outs by itself:
$ axfer transfer playback --sched-model=timer -D hw:0,0 -r 48000 -c2 -f
S16_LE /dev/urandom
PLAYBACK: Format 'Signed 16 bit Little Endian', Rate 48000 Hz, Channels
'Stereo'
Fail to process frames: Connection timed out
PLAYBACK: Expected 4611686018427387903frames, Actual 16304frames
How well is NO_PERIOD_WAKEUP tested/supported? Is it a bug in axfer or
perhaps some issue in kernel code?
From some debugging I did, I have my suspicions that it gets stuck on poll
in:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/sound/core/pcm_native.c?id=c06a2ba62fc401b7aaefd23f5d0bc06d2457ccc1#n3489
waiting for runtime->sleep to wake it, but seems like it never happens.
What do you think?
It's a regression added by a commit e5e6a7838b06 ("axfer: return ETIMEDOUT
when no event occurs after waiter expiration"), and the -ETIMEDOUT come
neither from ALSA PCM core nor alsa-lib. Thanks for your reporting!
* https://github.com/alsa-project/alsa-utils/commit/e5e6a7838b06
As a quick fix, please revert the commit. I'll post better fixes later.
After the revert, it looks work well under my hardware:
Yes, I can confirm, that it fixes the problem. Thanks for quick workaround!
