Chris seems to have correctly identified the issue. I tried reverting the xserver-xorg-video-intel to previous versions, but it had no affect.
I rebooted into an older kernel and i can still use compiz/unity. 3.16.0-6-generic : works 3.16.0-7-generic : fails 3.16.0-8-generic: fails ** Summary changed: - unity crashes on login, compiz cpu and memory intensive + compiz fails with intel_do_flush_locked failed: Invalid argument ** No longer affects: unity (Ubuntu) -- You received this bug notification because you are a member of Ubuntu-X, which is subscribed to xserver-xorg-video-intel in Ubuntu. https://bugs.launchpad.net/bugs/1355196 Title: compiz fails with intel_do_flush_locked failed: Invalid argument To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1355196/+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