[LAU] Alsa setup question

[hollundertee at gmx.net]

Hi there,

I didn't have access to the LA-lists for a number of months now, and the
list admin was not helpful. I subscribed with this crappy mail provider
now and hope that it will work. Sorry for advertisement and other crap
that might go along with it.

I do have some trouble setting up alsa the way I want it.
The machine is a laptop that I carry around and use at home.
What I want to have:
1) If on the road, the internal card (PCH) should be the default.
2) If at home, the usb card (UA25) should be the default.

I had this working rather reliably at some point, but it doesn't work
anymore.

I have the following in /etc/modprobe.d/alsa-base.conf to prevent race
conditions on boot:

options snd slots=snd_usb_audio,snd_hda_intel
options snd_usb_audio index=0
options snd_hda_intel index=1


However, I experience weird things with /etc/asound.conf, it gets
overwritten on every boot with garbage.
This is what it looks like when I boot without external interface:
defaults.ctl.card 1
defaults.pcm.card 1
defaults.pcm.card 1
defaults.pcm.card 1
defaults.pcm.card 1
defaults.pcm.card 1

When the external interface is plugged in on boot, it looks somewhat
like this (off the top of my head):
defaults.ctl.card 0
defaults.pcm.card 1
defaults.ctl.card 1
defaults.pcm.card 0
defaults.pcm.card 1
defaults.pcm.card 1
defaults.pcm.card 1
defaults.pcm.card 1

Obviously total garbage, and I have no idea what service tries to be
smart here. Any ideas? At least ~/.asoundrc does not get overwritten.



Also, is there a reliable way to do what I want?
Right now I have this in my ~/.asoundrc, but it does not do what I
want. I suspected that alsa would set the only device actually there as
default, but it does not, so with this setup I have no sound on the
road:
defaults.ctl.card 0
defaults.pcm.card 0


Thanks in advance for your help.
Regards,
hollunder