Bug#574844: SNDRV_PCM_IOCTL_RESUME failed: Function not implemented

[Reinhard Tartler]

reassign 574844 mplayer,libasound2
tags 574844 help
stop

Hi,

On Wed, Apr 07, 2010 at 01:41:24 (EDT), trentbuck at gmail.com wrote:

> # New evidence suggests this problem is mplayer-specific.
> reassign 575844 mplayer
> found 575844 1.0~rc3+svn20090405-1+b1
> thanks
>
> Consider the following transcript.  First, we generate a test file:
>
>     $ mplayer -really-quiet -ao pcm:fast -vo null -vc null http://he3.magnatune.com/all/01-Aurore-Gerard%20Satamian-lofi.mp3
>
> Plain aplay works:
>
>     $ sleep 10 && sudo tee <<<mem /sys/power/state & aplay audiodump.wav
>     [1] 5764
>     Playing WAVE 'audiodump.wav' : Signed 16 bit Little Endian, Rate 22050 Hz, Stereo
>     mem
>     Suspended. Trying resume. Done.
>     underrun!!! (at least -1270530282992.973 ms long)
>       C-c C-cAborted by signal Interrupt...
>     [1]+  Done                    sleep 10 && sudo tee /sys/power/state <<< mem
>
> Hmm, this works, too, though the delay between resuming the system and
> the audio continuing to play is much longer than with aplay.

This may or may not be caused by the resume code in mplayer:

,----[libao2/ao_alsa.c]
| static void audio_resume(void)
| {
|     int err;
| 
|     if (snd_pcm_state(alsa_handler) == SND_PCM_STATE_SUSPENDED) {
|         mp_msg(MSGT_AO,MSGL_INFO,MSGTR_AO_ALSA_PcmInSuspendModeTryingResume);
|         while ((err = snd_pcm_resume(alsa_handler)) == -EAGAIN) sleep(1);
|     }
|     if (alsa_can_pause) {
|         if ((err = snd_pcm_pause(alsa_handler, 0)) < 0)
|         {
|             mp_msg(MSGT_AO,MSGL_ERR,MSGTR_AO_ALSA_PcmResumeError, snd_strerror(err));
|             return;
|         }
|           mp_msg(MSGT_AO,MSGL_V,"alsa-resume: resume supported by hardware\n");
|     } else {
|         if ((err = snd_pcm_prepare(alsa_handler)) < 0)
|         {
|            mp_msg(MSGT_AO,MSGL_ERR,MSGTR_AO_ALSA_PcmPrepareError, snd_strerror(err));
|             return;
|         }
|     }
| }
`----


>     $ sleep 10 && sudo tee <<<mem /sys/power/state & mplayer -noconsolecontrols -quiet audiodump.wav
>     [1] 2832
>     MPlayer SVN-r29142-4.4.3 (C) 2000-2009 MPlayer Team
>
>     Playing audiodump.wav.
>     Audio only file format detected.
>     ==========================================================================
>     Opening audio decoder: [pcm] Uncompressed PCM audio decoder
>     AUDIO: 22050 Hz, 2 ch, s16le, 705.6 kbit/100.00% (ratio: 88200->88200)
>     Selected audio codec: [pcm] afm: pcm (Uncompressed PCM)
>     ==========================================================================
>     AO: [alsa] 48000Hz 2ch s16le (2 bytes per sample)
>     Video: no video
>     Starting playback...
>     mem
>     [AO_ALSA] Pcm in suspend mode, trying to resume.
>     [AO_ALSA] alsa-lib: pcm_hw.c:709:(snd_pcm_hw_resume) SNDRV_PCM_IOCTL_RESUME failed: Function not implemented
>       C-c C-c
>
>     MPlayer interrupted by signal 2 in module: play_audio
>
>     Exiting... (Quit)
>     [1]+  Done                    sleep 10 && sudo tee /sys/power/state <<< mem
>
> But this doesn't:
>
>     $ sleep 10 && sudo tee <<<mem /sys/power/state & mplayer audiodump.wav
>     [1] 5698
>     MPlayer SVN-r29142-4.4.3 (C) 2000-2009 MPlayer Team
>
>     Playing audiodump.wav.
>     Audio only file format detected.
>     ==========================================================================
>     Opening audio decoder: [pcm] Uncompressed PCM audio decoder
>     AUDIO: 22050 Hz, 2 ch, s16le, 705.6 kbit/100.00% (ratio: 88200->88200)
>     Selected audio codec: [pcm] afm: pcm (Uncompressed PCM)
>     ==========================================================================
>     AO: [alsa] 48000Hz 2ch s16le (2 bytes per sample)
>     Video: no video
>     Starting playback...
>     mem
>     [AO_ALSA] Pcm in suspend mode, trying to resume.
>     [AO_ALSA] alsa-lib: pcm_hw.c:709:(snd_pcm_hw_resume) SNDRV_PCM_IOCTL_RESUME failed: Function not implemented
>       C-c C-c
>
>     MPlayer interrupted by signal 2 in module: play_audio
>       C-c C-c
>
>     MPlayer interrupted by signal 2 in module: play_audio
>     [1]+  Done                    sleep 10 && sudo tee /sys/power/state <<< mem
>
> This makes me suspect some part of mplayer's terminal interaction
> code.

AFAIU the code, -noconsolecontrols does not do any terminal handling,
but 'just' controls on what events mplayer reacts. this is mainly useful
for the slave mode. I'm still a bit surprised why this makes a
difference here.

> These tests were done within Emacs' M-x shell, where TERM=dumb and
> stdio is connected to a tty (i.e. "test -t 0 -a -t 1 -a -t 2" passes).
>
> The behaviour above is consistent for kernels
> linux-image-2.6.32-3-amd64 (2.6.32-9) and linux-image-2.6.33-2-amd64
> (2.6.33-1~experimental.4).  For each, alsa-info.sh yields
> http://www.alsa-project.org/db/?f=3d1754592d25ecf773a04984473c7eefeda581de
> http://www.alsa-project.org/db/?f=df81bc3978db0e9a08685581da7614548dd41acc

in any case, this clearly needs an alsa expert. To me, this is clearly
an error from alsa-lib. I'm therefore reassinging this to both packages,
but I can also imagine that this needs to be fixed in the kernel.

-- 
Gruesse/greetings,
Reinhard Tartler, KeyID 945348A4