As an addendum, I've found that, on my laptop (Toshiba Portege R835-p70), this only happens when the lid is shut and the computer goes into sleep mode. Putting the computer into sleep through the power menu or 'pm-suspend' does not cause this issue. It seems to be isolated to the lid.
I do recieve 'not authorized' messages from the power manager when waking occasionally. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1283938 Title: Ubuntu 14.04 blank screen after wakeup from sleep To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-video-ati/+bug/1283938/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs