[LAU] Several USB cards position in /proc/asound/cards

Clemens Ladisch clemens at ladisch.de
Thu Oct 8 07:45:48 EDT 2009


Ismael Valladolid Torres wrote:
> options snd-intel8x0 index=0
> options snd-rme96 index=1
> options snd-usb-audio index=2
> 
> Now I bought an USB webcam, which also has a mic input. It appears in
> the system as another USB soundcard. The problem is that during boot
> as hotplug runs before anything else the first soundcard gets index 2
> as specified by alsa-base.conf but the second soundcard overrides
> index 0.

When a driver handles more than one device, you have to specify multiple
values for the index option, like this:

  options snd-usb-audio index=2,3

> How do I specify order of *several* USB soundcards in alsa-base.conf?

Look at the output of "lsusb" and "lsusb -n" for the vendor/product IDs
of the devices, then specify these IDs in the vid and/or pid options, in
hexadecimal.  For exampe, if your first USB device has IDs 0123:4567 and
the second 89ab:cdef, use the line

  options snd-usb-audio index=2,3 pid=0x4567,0xcdef


HTH
Clemens



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