Just tried 4.0.0 , and on first try I triggered this issue. I was, however, able to kill gnome-setting-daemon and then gnome-shell from a terminal. This then caused the lock screen to appear and I was able to log in. I've had this happen sometimes in the past before, so I consider this no change.
No suspect messages in dmesg or Xorg.0.log ** Tags added: kernel-bug-exists-upstream -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1442311 Title: Ubuntu 14.04 blank screen after wakeup from sleep To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1442311/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs