To my frustration, I noticed that my trusty Edirol UA-25 refused to work properly on Ubuntu 10.04. I spend quite some time tracking this problem down; eventually I found out that USB soundcards are moved down in priority.

The result of this are, among other things:

• Jackd won’t start
• Pd won’t find the soundcard
• Mixxx won’t start

In other words, no end of grief.
On Ubuntu, this started from 9.10 on (and because of this, also affects Pure:Dyne), on Debian this affects Squeeze.

Fortunately, there’s a simple solution!

On Debian’s bug-tracker, I found the following simple fix:
in /etc/modprobe.d/ create a file called local.conf. In this file, add the lines

alias snd-card-0 snd-usb-audio
options snd-usb-audio index=0

Reboot, or do sudo alsa reload and you’re done.