Comment 12 for bug 316125

Same problem, with (Asus G70, 2.6.28-4-server jaunty):

$ cat /proc/asound/cards
 0 [Intel ]: HDA-Intel - HDA Intel
                      HDA Intel at 0xfebf8000 irq 22
$ lspci | grep -i audio
00:1b.0 Audio device: Intel Corporation 82801H (ICH8 Family) HD Audio Controller (rev 03)

All channels are unmuted with alsamixer -c 0, but still no sound
The only sound I get is the microphone returning from the speakers (if I raise up the micro volume to the top)
mplayer behaviour is normal (and it plays), but no sound at all.

still investigating...