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

[Robert Krakora]

On Thu, Sep 29, 2011 at 2:36 AM, Takashi Iwai <tiwai at suse.de> wrote:

> 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
>   ftp://ftp.suse.com/pub/people/tiwai/snapshot/
>
>
> Takashi
>

Hi Takashi,

Thanks for the quick response.  Yes, the HD-audio stream open fails because
Asterisk has previously opened it.  aplay cannot open it (error -22).
However, dmix should remedy the situation.  It should provide software
mixing for Asterisk and aplay so that the output of both is mixed and output
to the analog audio channel.  I will try your latest drivers.

Best Regards,

-- 
Rob Krakora
MessageNet Systems
101 East Carmel Dr. Suite 105
Carmel, IN 46032
(317)566-1677 Ext 212
(317)663-0808 Fax