[alsa-devel] caiaq driver: audio 4 dj and jackd

Gabriel M. Beddingfield gabrbedd at gmail.com
Mon Dec 2 04:02:27 CET 2013

Is it possible to make all 4 ins/outs in the Audio 4 DJ available 
through the first substream device?

A user was having trouble using the NI Audio 4 DJ device with jackd. 
When jack connected, this 4-in/4-out device would appear as 2-in/2-out. 
This was the result of the fact that the channels are split up into 
stereo substreams.  I.e. the first two channels are found in hw:x,0,0 
and the last two channels are in hw:x,0,1.

The work-around was to use the `multi' plug-in to make these 2 PCM's 
appear as a single PCM.

There's several situations where this is a Good Thing, because it makes 
it easy for the user to treat the streams independently.

BUT... in the pro-audio case this is not a good thing at all.

Ideally, substream 0 would support 1, 2, or 4 channels (for both 
playback and capture).  When substream 0 is using more than 2 channels, 
then substream 1 would return EBUSY when in use.

So... would it be possible to do this in the caiaq driver?


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