Subject: Re: [linux-audio-user] 2.6.8-rc1-mm1 [and alsa xrun debugging]
From: Lee Revell (rlrevell_AT_joe-job.com)
Date: Fri Jul 16 2004 - 23:08:33 EEST
On Fri, 2004-07-16 at 10:25, Florian Schmidt wrote:
> after reading lee's email i had to try this kernel.. so i went over to www.de.kernel.org, grabbed 2.6.8-rc1 and patched it up with this patch:
>
> http://www.ussg.iu.edu/hypermail/linux/kernel/0407.1/1453.html
>
> On first sight it looks very good. many of the sporadic xruns i experienced with jack in RT mode are gone. even a "find /" parallel to a "make bzImage" seems not to provoke any xruns [i use ext3]. But: i use fluxbox and it supports desktop wheeling [switching desktop via scrollwheel - very handy] and doing this excessively and rapidly provokes xruns easily. Also starting mozilla just provoked an xrun..
>
> Well to provie more detailed info i thought i'd turn on xrun tracing. So here are the steps i took:
>
> 1] enabled debugging in the alsa drivers [i did that when i built the 2.6.8rc1mm1 kernel and the included alsa modules.
>
> 2] mango:/home/tapas# echo 1 > /proc/asound/card0/pcm0p/xrun_debug
> mango:/home/tapas# echo 1 > /proc/asound/card0/pcm0c/xrun_debug
>
> 3] started jackd -R -d alsa -p 512 and provoked xruns, but the traces are nowhere to be found.. where should i look? /var/log/messages - nothin; /var/log/debug - nothing; /var/log/dmesg - nothing.. Maybe i'm just stooopid here.. Please enlighten me.
>
> Thanks,
> Flo
You have to echo 2 > /proc/foo/xrun_debug. Then, if you produce an
XRUN, dmesg should contain a stack trace.
Lee
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