[ALSA - driver 0002070]: Hard lockup from aplay with low buffersizes on Tascam us-122 (snd_usb_usx2y)

[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=2070> 
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Reported By:                jaime
Assigned To:                karsten
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Project:                    ALSA - driver
Issue ID:                   2070
Category:                   USB - usb-usx2y
Reproducibility:            always
Severity:                   crash
Priority:                   normal
Status:                     assigned
Distribution:               Gentoo ~x86
Kernel Version:             2.6.17-rc1
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Date Submitted:             04-25-2006 23:07 CEST
Last Modified:              04-26-2006 23:29 CEST
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Summary:                    Hard lockup from aplay with low buffersizes on
Tascam us-122 (snd_usb_usx2y)
Description: 
Hi.

Here's the original I'm playing (440Hz sine wave):
www.carbon.eclipse.co.uk/origSine.wav

aplay --buffer-size=1024 origSine.wav sounds great:
www.carbon.eclipse.co.uk/aplay1024.wav

aplay --buffer-size=512 origSine.wav sounds bad:
www.carbon.eclipse.co.uk/aplay512.wav

aplay --buffer-size=256 origSine.wav sounds very bad:
www.carbon.eclipse.co.uk/aplay256.wav

aplay --buffer-size=128 origSine.wav gives only a very short click,
and then locks up the machine completely:
www.carbon.eclipse.co.uk/aplay128.wav

I've tried this using different usb cards/controllers, and I get the
same problem, so I think it is an alsa driver problem.

Thank you for any help you can offer.

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----------------------------------------------------------------------
 karsten - 04-26-06 23:19 
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$ cat /sys/module/snd_usb_usx2y/nrpacks

and if this shows the default 4,
please try again with nrpacks 1.

(rmmod snd_usb_usx2y; modprobe snd_usb_usx2y nrpacks=1)

ultimate info would be a stack backtrace of the crash:
you'd have to set up a serial console or a netconsole for that.
browse kernel/Documentation or google for "how to"s.

----------------------------------------------------------------------
 karsten - 04-26-06 23:29 
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just red again:

aplay --buffer-size=128 isn't really possible:
thats 2 period with 64frames each.
USB1.1 tranfers data at 1ms chunks: that'll be like 44 to 48 frames.
so jitter is to big.

none the less it shouldn't crash the machine...

Issue History
Date Modified  Username       Field                    Change              
======================================================================
04-25-06 23:07 jaime          New Issue                                    
04-25-06 23:07 jaime          Distribution              => Gentoo ~x86     
04-25-06 23:07 jaime          Kernel Version            => 2.6.17-rc1      
04-26-06 16:23 jaime          Note Added: 0009514                          
04-26-06 23:19 karsten        Note Added: 0009526                          
04-26-06 23:29 karsten        Note Added: 0009527                          
======================================================================




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