Comment 12 for bug 586418

A patch is in upstream: http://git.kernel.org/?p=linux/kernel/git/tiwai/sound-2.6.git;a=commit;h=5d4abf93ea3192cc666430225a29a4978c97c57d

A dkms module is in my ppa: alsa-intel-hda-optiplex-dkms, current prognosis is that it will build in three days...!

So wait a few days, then you can either pick it from there or from https://wiki.ubuntu.com/Audio/InstallingLinuxAlsaDriverModules