[rsv]

what I did was purge and install all my alsa packages again.

Like this:

sudo aptitude search "alsa" | grep "^i"

i alsa-base - ALSA driver configuration files
i alsa-oss - ALSA wrapper for OSS applications
i A alsa-utils - Utilities for configuring and using ALSA
i alsamixergui - graphical soundcard mixer for ALSA soundca
i gstreamer0.10-alsa - GStreamer plugin for ALSA


Then I do a :

sudo aptitude purge alsa-base ..... all of them


then I do:

sudo aptitude install alsa-base ... the same packages...


and after several test reboots all works..

ubuntu 12.04 - latest updates on a Dell l502x aka xps 15.