Just ran into this same problem on 14.04 with kernel 3.16.0-46-generic. Attaching relevant dmesg output.
** Attachment added: "kernel_stack_trace.txt.bz2" https://bugs.launchpad.net/ubuntu/+source/fglrx-installer/+bug/1338177/+attachment/4454296/+files/kernel_stack_trace.txt.bz2 -- You received this bug notification because you are a member of Ubuntu-X, which is subscribed to fglrx-installer in Ubuntu. https://bugs.launchpad.net/bugs/1338177 Title: BUG: soft lockup - CPU#0 stuck for 23s! [Xorg:1295] To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/fglrx-installer/+bug/1338177/+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