[ALSA - lib 0001074]: pcm_dmix hangs on device close

[bugtrack@alsa-project.org]

A NOTE has been added to this issue.
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<https://bugtrack.alsa-project.org/alsa-bug/view.php?id=1074> 
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Reported By:                ikonst
Assigned To:                
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Project:                    ALSA - lib
Issue ID:                   1074
Category:                   pcm - digital audio
Reproducibility:            always
Severity:                   minor
Priority:                   normal
Status:                     new
======================================================================
Date Submitted:             04-24-2005 08:48 CEST
Last Modified:              05-12-2005 13:50 CEST
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Summary:                    pcm_dmix hangs on device close
Description: 
The fix in pcm_dmix.c revision 1.71 causes the following regression:

Everytime I access a Flash site thru my 'aoss'-wrapped Mozilla, it hangs:

https://bugtrack.alsa-project.org/alsa-bug/view.php?id=0  0x40a951c3 in poll ()
from /lib/tls/libc.so.6
https://bugtrack.alsa-project.org/alsa-bug/view.php?id=1  0x4001a1fd in poll ()
from /usr/lib/libaoss.so
https://bugtrack.alsa-project.org/alsa-bug/view.php?id=2  0x40c7bf78 in
snd_pcm_wait_nocheck (pcm=0x9a7a6a0, timeout=-1)
    at pcm.c:2234
https://bugtrack.alsa-project.org/alsa-bug/view.php?id=3  0x40cb27fb in
snd_pcm_dmix_drain (pcm=0x9a7a6a0) at pcm_dmix.c:504
https://bugtrack.alsa-project.org/alsa-bug/view.php?id=4  0x40c79bd4 in
snd_pcm_drain (pcm=0xfffffffc) at pcm.c:1044
https://bugtrack.alsa-project.org/alsa-bug/view.php?id=5  0x40c8cbb7 in
snd_pcm_generic_drain (pcm=0xfffffffc) at
pcm_generic.c:151
https://bugtrack.alsa-project.org/alsa-bug/view.php?id=6  0x40c79bd4 in
snd_pcm_drain (pcm=0xfffffffc) at pcm.c:1044
https://bugtrack.alsa-project.org/alsa-bug/view.php?id=7  0x40bb24e7 in
lib_oss_pcm_close () from /usr/lib/libalsatoss.so.0
https://bugtrack.alsa-project.org/alsa-bug/view.php?id=8  0x400199b4 in close ()
from /usr/lib/libaoss.so
https://bugtrack.alsa-project.org/alsa-bug/view.php?id=9  0x441712b9 in
PlatformSoundMix::UnlockAudioCallback ()
   from /usr/lib/flashplugin-nonfree/libflashplayer.so
...

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----------------------------------------------------------------------
 chtephan - 05-12-05 13:34 
----------------------------------------------------------------------
Of, course, a non-blocking fd does not block, but the timer fd is not
opened non-blocking.

Or why do you explain he doesn't leave with EAGAIN here, but hangs in
schedule() waiting for something to happen? ;)

The pending timer event flush function should work with both blocking and
non-blocking timer fds. Except of course if the timer fds shouldn't have
been opened blocking in the first place.

> if ((file->f_flags & O_NONBLOCK) != 0 || result > 0) {
>         err = -EAGAIN;
>         break;
> }
>
> set_current_state(TASK_INTERRUPTIBLE);
> init_waitqueue_entry(&wait, current);
> add_wait_queue(&tu->qchange_sleep, &wait);
>
> spin_unlock_irq(&tu->qlock);
> schedule();
> spin_lock_irq(&tu->qlock);

----------------------------------------------------------------------
 tiwai - 05-12-05 13:50 
----------------------------------------------------------------------
But the timer in dmix is supposed to be opened in non-blocking mode.
See snd_timer_open() in pcm_direct.c.

Issue History
Date Modified  Username       Field                    Change              
======================================================================
04-24-05 08:48 ikonst         New Issue                                    
05-09-05 17:33 chtephan       Note Added: 0004627                          
05-09-05 17:53 chtephan       Issue Monitored: chtephan                    
05-09-05 20:41 chtephan       File Added: timer-flush-blocking.diff             
      
05-09-05 20:42 chtephan       Note Added: 0004629                          
05-11-05 17:23 ikonst         Note Added: 0004638                          
05-11-05 18:11 tiwai          Note Added: 0004639                          
05-12-05 13:34 chtephan       Note Added: 0004641                          
05-12-05 13:50 tiwai          Note Added: 0004642                          
======================================================================




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