Re: [Alsa-devel] Re: 2.6.10-mm1: ALSA ac97 compile error with CONFIG_PM=n

From: Mark_H_Johnson
Date: Fri Jan 07 2005 - 09:58:04 EST


> And if you want to find out who is using it then try fuser /dev/dsp,
> fuser /dev/snd/*, or lsof.

Hmm. I figured out which application is "getting in my way" but am not
quite sure why I have a problem opening the audio / what I should do
about it.

On my system...

# fuser /dev/snd/* /dev/dsp
/dev/snd/pcmC0D0p: 2972 2972m
# ps -fe | grep 2972
u21305 2972 2936 0 10:15 ? 00:00:02 artsd -F 10 -S 4096 -a alsa
-s 60 -m artsmessage -c drkonqi -l 3 -f
root 4915 3407 0 11:08 pts/7 00:00:00 grep 2972
# fuser /dev/snd/* /dev/dsp
[I caused a console beep here using backspace]
# fuser /dev/snd/* /dev/dsp
/dev/snd/pcmC0D0p: 2972 2972m

OK, so artsd wakes up on some trigger and then waits around a while
expecting to get some more audio to process. I see it is a user of
/dev/snd/pcmC0D0p but not a user of /dev/dsp. Yet when I attempt to
open /dev/dsp, I get an error.

When I successfully run latencytest (and open /dev/dsp) I see...

# fuser /dev/snd/* /dev/dsp
/dev/dsp: 9156

which is the pid of latencytest.

Can someone please explain the relationship between these devices
and why access to one of these devices prevents access to another?
This is certainly confusing to me.

Thanks.
--Mark

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