For a while now, my sound has not been working in Ubuntu. It used to play OK, but after some upgrade (might have been distro upgrade to 9.10), it stopped working. I'm currently running 10.04 on an amd64 architecture. I'm using the builtin audio on a Foxconn motherboard, it's an ATI / Intel HDA chip with an Azalia controller, apparently it's using the Realtek ALC1200 codec. All the gory details here.

I found a nice sound troubleshooting tutorial here, which is well-written and pretty extensive, however, I fail to look up the supported "models" for my soundcard.

The troubleshooting page says to look for a section giving the codec used by your soundcard, which looks like this for me:

!!HDA-Intel Codec information
!!---------------------------
--startcollapse--

Codec: Realtek ALC1200

Then, I'm supposed to lookup the models for that codec in the file Documentation/ALSA-Configuration.txt in the appropriate directory of ALSA's git repository. Mine actually pointed me to a separate file, Documentation/HD-Audio-Models.txt, which, for my driver version is located here and contains no section related to ALC1200 codecs.

I tried putting the driver options probe-mask=1 and model=auto in a config file for modprobe, as suggested elsewhere, but this just lead to snd-hda-intel not able to load at all anymore. I also tried installing the linux-backports-modules-alsa package for my kernel, because the description sounded promising, but that didn't change anything, either.