This is happening since I upgraded from saucy to trusty.
Installing the latest mainline kernel from http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.14-rc1-trusty/ solves the issue.
This is happening since I upgraded from saucy to trusty.
Installing the latest mainline kernel from http:// kernel. ubuntu. com/~kernel- ppa/mainline/ v3.14-rc1- trusty/ solves the issue.