This bug might be related to this:
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/704401
From that page, it looks like adding options snd-hda-intel model=6stack-dig to /etc/modprobe.d/alsa-base.conf might fix it.
This bug might be related to this:
https:/ /bugs.launchpad .net/ubuntu/ +source/ linux/+ bug/704401
From that page, it looks like adding d/alsa- base.conf might fix it.
options snd-hda-intel model=6stack-dig
to /etc/modprobe.