Waht helped for me was upgrading to 12.04.2 with kernel 3.5 as described here
http://askubuntu.com/questions/279391/quantal-backported-kernel-in-12-04-2-whats-going-on-there
Waht helped for me was upgrading to 12.04.2 with kernel 3.5 as described here
http:// askubuntu. com/questions/ 279391/ quantal- backported- kernel- in-12-04- 2-whats- going-on- there