Comment 16 for bug 318942

What I did before installed drivers was going to System>Preferences>Sound and change everything to ALSA. Also I've added my user to pulse group (System -> Administration -> Groups & Users -I think is that option in English, since I use ubuntu in spanish-). Then reboot.

Also, you should try another models in line "options snd-hda-intel model=dell-m4-1" in alsa.conf file if your sound card is different, as described here: https://answers.launchpad.net/ubuntu/+question/64930