[alsa-devel] dmix problems with analog out (HDMI out works fine with dmix)

Takashi Iwai tiwai at suse.de
Thu Sep 29 08:36:53 CEST 2011

At Wed, 28 Sep 2011 12:29:05 -0400,
Robert Krakora wrote:
> Hi All,
> I am using ALSA 1.0.24 with the attached asound.conf.  I am attempting to
> share (mix) the analog output between Asterisk and aplay.  However, when
> Asterisk is running, my application throws an error when attempting to play
> a wave file via aplay.  If I stop Asterisk, aplay plays the wave file just
> fine.  If I remove the asound.conf file, Asterisk and aplay are both happy
> and share the analog output just find with the default ALSA dmix
> implementation.  However, we need this asound.conf to work for us for other
> reasons.  What is wrong with it.  I have even tried replacing dmix with
> dshare and get the same bad behavior.  We are running CentOS 6.0.  As a
> caveat, I am attempting to use dmix with analog audio.  If I use it with
> HDMI audio, it works flawlessly (same asound.conf with tweek to specify
> HDMI).  Thanks in advance for your help.
> [root at devkrakorar snd]# su silentm -c "aplay -Dplug:dmixer
> /usr/share/sounds/alsa/Front_
> Center.wav"
> ALSA lib pcm_hw.c:1293:(snd_pcm_hw_open) open '/dev/snd/pcmC0D0p' failed
> (-22): Invalid argument
> ALSA lib pcm_dmix.c:1068:(snd_pcm_dmix_open) unable to open slave
> aplay: main:660: audio open error: Invalid argument
> [root at devkrakorar snd]#

Looks like the open of HD-audio stream failed by some reason.
When you open via aplay, is the corresponding stream already opened
by another?  Take a look at /proc/asound/card0/pcm0p/sub0/* files.

Also, try the latest alsa-driver snapshot in


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