I'm able to get sound and the touchpad working on the Toshiba A75. I'm using Slackware 10 but this might be helpful:
As you say, sound is AC 97, but the exact driver needed is snd-atiixp (apparently there are several chipsets/modules associated with AC97). Try to insmod or modprobe snd-atiixp and sound should work. I had a problem in Slackware with the module snd-atiixp-modem also getting loaded and messing up the sound, so I added that to /etc/hotplug/blacklist, restarted, made sure the snd-atiixp module was getting loaded, and sound worked.
This worked for me in the xorg.conf file:
Option "Protocol" "auto"
Option "Device" "/dev/mouse"
Option "Emulate3Buttons" "true"
Option "Emulate3Timeout" "50" # timeout in milliseconds (default is 50ms)
Option "ZAxisMapping" "4 5"
Option "SendCoreEvents" "true"
More notes on setting up this laptop at:
If you have any more tips on it, please let me know, firstname.lastname@example.org