This seems to be a regression of the xf86-vidoe-intel driver. You can take a look on comment #44 on this bug report in ubuntu for a patch to revert the commit that produces this problem:
https://bugs.launchpad.net/ubuntu/+source/fglrx-installer- updates/+bug/1068404 -- You received this bug notification because you are a member of Ubuntu-X, which is subscribed to the bug report. https://bugs.launchpad.net/bugs/1068404 Title: 1002:6760 Switchable graphics on Radeon HD 6400M not working again To manage notifications about this bug go to: https://bugs.launchpad.net/xserver-xorg-video-intel/+bug/1068404/+subscriptions _______________________________________________ Mailing list: https://launchpad.net/~ubuntu-x-swat Post to : ubuntu-x-swat@lists.launchpad.net Unsubscribe : https://launchpad.net/~ubuntu-x-swat More help : https://help.launchpad.net/ListHelp
