[ALSA - driver 0000589]: ICH5 S/PDIF audio drops out occasionally

[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=589> 
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Reported By:                squarooticus
Assigned To:                
======================================================================
Project:                    ALSA - driver
Issue ID:                   589
Category:                   PCI - intel8x0
Reproducibility:            always
Severity:                   minor
Priority:                   normal
Status:                     new
Distribution:               Debian Unstable (sid)
Kernel Version:             2.6.7
======================================================================
Date Submitted:             10-21-2004 02:42 CEST
Last Modified:              11-18-2004 17:51 CET
======================================================================
Summary:                    ICH5 S/PDIF audio drops out occasionally
Description: 
I'm using the on-board audio of my Abit IC7-MAX3 ("Intel Corp. 82801EB/ER
(ICH5/ICH5R) AC'97 Audio Controller (rev 02)") with ALSA driver
snd_intel8x0 for my home theater setup.  In every application I've tried,
which includes mythtv, xine, and ogg123, through both native alsa and OSS
emulation, the audio output from the S/PDIF port drops out for a second
every so often---maybe once a minute, or every few minutes; it's not
periodic.

I don't know whether analog output also drops out, since I don't have
analog output hooked up or enabled.

This is with the CVS build as of October 19.  My asound.conf is:

pcm.krose-dmix {
  type dmix
  ipc_key 3516
  ipc_key_add_uid yes
  slave {
        pcm "hw:0,4"
        period_time 0
        period_size 4096
        #buffer_size 16384
        buffer_size 131072
        period_time 84000
        buffer_time 340000
        rate 48000
        channels 2
  }
  bindings.0 0
  bindings.1 1
}

pcm.dsp0 {
  type plug
  slave.pcm "krose-dmix"
}

ctl.mixer0 {
 type hw
 card 0
}

pcm.!default {
 type plug
 slave.pcm "krose-dmix"
}

I can't find any options to compile in debug logging: I'm not really sure
what the cause of the drop out is, e.g., buffer underrun, PCI contention,
etc.  I'm happy to spend time to try to debug this, but I need a starting
point.

Of course, it'd also be great to know if anyone has ever seen this kind of
behavior before.  I don't believe the SPD/IF port is turning itself off
because the receiver doesn't blip, which normally it would if the input
were to disappear temporarily.

The CPU is a 3.2G P4 with hyperthreading turned on.  I never see the CPU
usage go above 50%.

Interestingly, I see similar behavior on my dual Opteron machine with an
AMD-8111 audio controller using the same driver (snd_intel8x0).  I never
had this problem with the emu10k1 driver when I was using SB Lives, but I
have run into PCI slot limitations in my HTPC, so I have to use mobo
audio.

Suggestions?
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----------------------------------------------------------------------
 squarooticus - 11-16-04 05:14 
----------------------------------------------------------------------
More info: this problem occurs with another digital receiver, so the
problem is either with (a) the software, (b) the mobo hardware, or (c) the
cable.  I will try to eliminate (c) this week. :)  FWIW, the drop-out is
much shorter on this receiver (Yamaha HTR-5650) than on the original one
(Marantz SR-7000).  It's unclear to me whether this means the S/PDIF
signal is being interrupted, or if an underrun of the AC3 data is enough
to cause this effect.

----------------------------------------------------------------------
 tiwai - 11-18-04 17:51 
----------------------------------------------------------------------
You can turn on the xrun-detection by writing to a proc file,

   # echo 2 > /proc/asound/card0/pcm4p/xrun_debug

where the directory corresponds to the PCM device to check.
Then you can know at least wheter detectable xrun happened.

Issue History
Date Modified  Username       Field                    Change              
======================================================================
10-21-04 02:42 squarooticus   New Issue                                    
10-21-04 02:42 squarooticus   Distribution              => Debian Unstable (sid)
10-21-04 02:42 squarooticus   Kernel Version            => 2.6.7           
10-21-04 23:40 squarooticus   Issue Monitored: squarooticus                    
10-27-04 16:54 squarooticus   Note Added: 0002275                          
11-10-04 12:26 tiwai          Note Added: 0002367                          
11-12-04 06:23 squarooticus   Note Added: 0002392                          
11-15-04 20:24 squarooticus   Note Added: 0002419                          
11-16-04 02:50 squarooticus   Note Added: 0002423                          
11-16-04 05:14 squarooticus   Note Added: 0002424                          
11-18-04 17:51 tiwai          Note Added: 0002452                          
======================================================================




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