[alsa-devel] Use of default device with snd_pcm_link()

Devin Heitmueller dheitmueller at kernellabs.com
Mon Dec 28 01:59:28 CET 2009

I am working on some code which captures from one PCM device and plays
to another, based off of the latency.c found in alsa-lib.  I noticed
something strange:

The code works if I set the capture device to hw:1,0 and playback
device to hw:0,0.  However, if I change the playback device to
"default:0", the snd_pcm_link() call fails with -ENOSYS (error 38).

If I dump out the properties, I can see that the the default device
*is* mapped to device 0,0, so it's not clear why the behaviour would

My goal was just to playback to whatever the default device is, and I
was under the impression that default:0 should be equivalent to
"hw:0,0".  Can anyone offer any brief explanation as to why the
snd_pcm_link() call would fail?

Thanks in advance,


Devin J. Heitmueller - Kernel Labs

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