[ALSA - driver 0000583]: xruns when playing audio or video files

[bugtrack@alsa-project.org]

A BUGNOTE has been added to this bug.
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https://bugtrack.alsa-project.org/alsa-bug/bug_view_page.php?bug_id=0000583
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Reported By:                KAtiOS
Assigned To:                tiwai
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Project:                    ALSA - driver
Bug ID:                     583
Category:                   PCI - atiixp
Reproducibility:            always
Severity:                   major
Priority:                   normal
Status:                     assigned
Distribution:               Gentoo Linux
Kernel Version:             2.6.9_rc4
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Date Submitted:             10-15-2004 16:27 CEST
Last Modified:              10-15-2004 22:17 CEST
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Summary:                    xruns when playing audio or video files
Description: 
I get xruns when playing files.
I tested with lots of 2.6 kernels, up to 2.6.9_rc4 with the same results.
It seems that mplayer with sdl output works fine, but xruns with alsa.
Using acpi=off or pci=noacpi helps in mplayer but not in vdr (with
softdevice plugin - using alsa).



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----------------------------------------------------------------------
 lee - 10-15-2004 18:43 CEST 
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This is a kernel issue, not an ALSA bug.  If you want xrun-free operation
you HAVE to use a kernel patched for low latency.  Please close this bug.

----------------------------------------------------------------------
 KAtiOS - 10-15-2004 18:51 CEST 
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Since when a low latency [so.. patched] kernel is needed to listen to music
and play video correctly?
Given that the processor isn't particulary weak and that's the only task
of the system, it shouldn't be hard to keep pace.

----------------------------------------------------------------------
 lee - 10-15-2004 19:02 CEST 
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OK, you are right, you should not need to patch the kernel to avoid massive
xruns with regular AV playback.  The reason I say it's a kernel issue is
that disabling ACPI seems to fix the problem.

Do you get fewer xruns if you disable xrun debugging?  This can cause a
cascade effect where a single xrun triggers hundreds of them due to printk
overhrad.

Also, does it work OK with a 2.4 kernel?

----------------------------------------------------------------------
 KAtiOS - 10-15-2004 19:12 CEST 
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Disabling ACPI seems to help with mplayer, but mplayer causes troubles only
a few times in the duration of a music, whereas VDR got several xruns a
second, whether ACPI is disabled or not. 
I tried with xrun debugging desactived but VDR acts the same (visibly at
least).

I haven't used a 2.4 in months, would it helped it I tried with one?

----------------------------------------------------------------------
 KAtiOS - 10-15-2004 19:24 CEST 
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Also note that I tried in the past with and without preempt without making
a major difference that I can still think of.
(preemp activated right now btw)

----------------------------------------------------------------------
 lee - 10-15-2004 19:29 CEST 
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I get the occasional xrun with mplayer even with the latest 2.6 low latency
kernels.  I figure it's a bug in mplayer's ALSA support.  VDR I don't
know.  Do other users of that program report the same issue?

There are many, many apps out there with buggy ALSA support but good OSS
support.  Try a known good app like aplay or alsaplayer.

----------------------------------------------------------------------
 KAtiOS - 10-15-2004 20:28 CEST 
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Humm.. yes but since mplayer seems to be working ok with audio files, I
don't think alsaplayer will help.
I just tested, I have xrun with a video played with mplayer (acpi off)
Any video player I could test?

----------------------------------------------------------------------
 lee - 10-15-2004 22:17 CEST 
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If audio plays back OK but AV playback causes xruns, then this cannot be an
ALSA issue.  Mplayer's ALSA support is known to be buggy.  I am not sure
there is a video player with known good ALSA support.  You might want to
ask on the alsa-user list.

Bug History
Date Modified  Username       Field                    Change              
======================================================================
10-15-04 16:27 KAtiOS         New Bug                                      
10-15-04 16:27 KAtiOS         Distribution              => Gentoo Linux    
10-15-04 16:27 KAtiOS         Kernel Version            => 2.6.9_rc4       
10-15-04 18:43 lee            Bugnote Added: 0002168                       
10-15-04 18:51 KAtiOS         Bugnote Added: 0002169                       
10-15-04 19:02 lee            Bugnote Added: 0002170                       
10-15-04 19:12 KAtiOS         Bugnote Added: 0002171                       
10-15-04 19:24 KAtiOS         Bugnote Added: 0002172                       
10-15-04 19:29 lee            Bugnote Added: 0002173                       
10-15-04 20:28 KAtiOS         Bugnote Added: 0002174                       
10-15-04 22:17 lee            Bugnote Added: 0002175                       
======================================================================


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