Hi Pierre-Louis, On Mon, 2009-08-24 at 12:26 -0500, pl bossart wrote: > Hi, > I have a piece of custom hardware that provides 7 independent PCM > outputs. This is not intended for multichannel playback, the content > on each output can be completely different; playback will not be > synchronized and will start separately. The only restriction is that > all outputs rely on the same baserate and share the same bitclock, > i.e. all the outputs work at 48kHz. > > >From the mailling list archives, subdevices seem to be relevant when > doing hw mixing or when lots of streams are handled. None of this > applies to my case. Also it looks like PulseAudio knows nothing about > subdevices in its detection loop, meaning the user would need to > manually add some load-module commands in the PulseAudio configuration > files. And last but not least, I didn't see very many lines of code > (and no documentation) that showed how subdevices are > registered/handled, etc. > > My conclusion is that multiple devices would seem like a much better > option. But I wanted to check with the community that I am on the > right track. Thanks for your feedback! > - P Fwiw, I worked on a similar piece of hardware a few years back (WM9713). It too had a shared 48kHz clock (AC97) and 3 independent outputs. I found creating a single card with 3 pcms worked very well in this case and kept the code simple. I could independently play different audio data to each pcm with different start/stop times. There is some example code in the ASoC WM9713 codec driver and in soc-core.c HTH Liam _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
