I can confirm the bug with DRI_PRIME Current setup is Intel Ivy Bridge + AMD Radeon 7730M
Reverting the following packages and their dependencies to their trusty-update version fixed the issue (Following packages with their dependencies) xserver-xorg-input-all xserver-xorg-input-wacom xserver-xorg-video-glamoregl xserver-xorg-input-synaptics xserver-xorg-input-evdev xserver-xorg-core xserver-xorg-input-mouse xserver-xorg-video-vesa xserver-xorg-video-mach64 xserver-xorg-video-fbdev xserver-xorg xserver-xorg-input-vmmouse xserver-xorg-video-modesetting xserver-xorg-video-r128 The problem most probably is contained in the package xserver-xorg, since most of these dependencies shouldn't affect prime (input) -- You received this bug notification because you are a member of Ubuntu-X, which is subscribed to xorg in Ubuntu. https://bugs.launchpad.net/bugs/1388647 Title: DRI_PRIME=1 has no effect in Ubuntu 14.10 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/xorg/+bug/1388647/+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