I had some troubles to get any sound out of my Toshiba notebook with the recent kernels 2.6.21 and 2.6.22. My sound card is
00:14.2 Audio device: ATI Technologies Inc SB450 HDA Audio (rev 01)
However it is working with 2.6.23-rc4 vanilla kernel. I don’t know whether it is a problem in alsa or in the kernel itself but after several hours of googling I finally got it playing.
Firstly you have to put in /etc/modprobe.d/aliases or whatever module aliases file you have the following
alias snd-card-0 snd-hda-intel
and secondly in /etc/modprobe.d/alsa-base this one
options snd-hda-intel model=auto enable=1 index=0
and voila! Adjust your sound levels with alsamixer 
