Comment 33 for bug 497546

Try any 2.6.34 kernel, and do this (that's what's the patch does):
sudo modprobe -r snd-hda-intel
sudo modprobe snd-hda-intel model=ideapad

Then test your audio. This should

If this works you can add a file in /etc/modprobe.d/, containing:
options snd-hda-intel model=ideapad
so that your fix is permanent. For example:
echo "options snd-hda-intel model=ideapad" | sudo tee /etc/modprobe.d/sound-fix-dell-conexant

Please report here if this works (or doesn't) so that future kernel versions can include the fix.