[alsa-devel] USB-Audio.conf routing and dmix

[Raymond Yau]

>
> I have a bose USB audio 5.1 device, a generic USB audio device.
>
> I noticed that the proper channels routing was missing from the default
generic
> USB pcm, but dmix was used. And for the surround pcms I noticed it was the
> other way around!
>
> I did modify the default pcm to include a routing plugin. I put 8
channels in
> the routing plugin. I guess the proper way would be to detect the hw card
> number of channels and select a route plugin configuration with the
correct
> count of channels (maybe their is a function to get that info?).
>
> I linked the surround51 and surround71 pcms with the 'disable-able' dmix
> section from the default pcm.
>
> I did not touch the surround40* pcms, surround pcms which are specific to
some
> cards and the iec958 ones.
>
> http://filebin.ca/214UTT8fBnUm/USB-Audio.conf
>
>

Post the output of your usb audio

lsusb -vvvv

Most likely your usb audio device does not support stereo

Post output of alsa-info.sh

Pulseaudio don't support if your volume control have more than two channels

http://cgit.freedesktop.org/pulseaudio/pulseaudio/commit/src/modules/alsa?id=527078523815587bfd021bc1d10782403e9b3e84