[TriLUG] ALSA and card ordering

[crimsun at fungus.sh.nu]

On Thu, Apr 28, 2005 at 09:19:42AM -0400, Andrew Perrin wrote:
> Any ideas on how to tell the system to load the real sound card as card0
> and snd-bt878 as card 1?

First of all, you need alsa-base (>= 1.0.8-1), because the patches for
ordering were applied for that revision.

Second, your alsa-driver/kernel needs to be aware of this new ordering.
So far, the Debian- and Ubuntu-provided kernels have included this
patch (Sarge/Sid and Hoary+, respectively).

Third, the "proper" (i.e., the way that upstream ALSA has adopted for
1.0.9, which Debian has been using since 1.0.8-1) method is to insert
the appropriate line into /etc/modprobe.d/alsa-base, _not_
/etc/modprobe.conf, because the presence of the latter will cause all
scripts in /etc/modprobe.d/ to be skipped, and that is most definitely
_not_ what you intend.

The negative-mask patch that Thomas coded allows the user to tell ALSA
to prefer a subset of drivers be loaded as non-primary (e.g., not card
0). In your scenario, you'd use:

echo "options snd-bt87x index=-2" | sudo tee -a /etc/modprobe.d/alsa-base

You may then either reboot, or remove the ALSA driver modules for your
two sound devices manually and reinsert them.

-- 
Daniel T. Chen          crimsun at fungus.sh.nu
GPG key:   www.sh.nu/~crimsun/pubkey.gpg.asc
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