I had the same problem. My sound card is Intel ... AC'97 Audio Controller.
I added this line into /etc/modprobe.conf:
options snd-intel8x0 ac97_quirk=3 (if 3 doesn't work, try 1, 2, or 4)
and sound card has worked properly since then. (reboot is necessary)
But this probably solves only Intel sound card problems.
Tomas Vlcek
PS: Good luck