From mboxrd@z Thu Jan  1 00:00:00 1970
From: Raymond Yau <superquad.vortex2@gmail.com>
Subject: dmix and dsnoop
Date: Sun, 14 Feb 2010 15:26:08 +0800
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why do dmix and dsnoop 's slave alway open subdevice 0 ?

for those hardware mixing sound cards which has two or more playback
subdevices or hda-intel which may have 3 recording subdevices

when subdevice 0 is opened by another application ,

dmix / dsnoop always fail even when there are available subdevices

aplay -v -Dplug:dmix test.wav
ALSA lib pcm_dmix.c:1010:(snd_pcm_dmix_open) unable to open slave
aplay: main:654: audio open error: Device or resource busy



arecord -v -Dplug:dsnoop:1 -f cd -d20 tt.wav
ALSA lib pcm_dsnoop.c:593:(snd_pcm_dsnoop_open) unable to open slave
arecord: main:654: audio open error: Device or resource busy