I think I am experiencing the same issue as Thomas Maaß, though I am not convinced that it is the same behavior as the initial report. Namely, sometimes the display does not turn on when light-locker should be prompting for a password (I think I have seen this both when returning from hibernation and after a "normal" lock-screen event when the machine should still be running), though other times the display does turn on. Switching to a text terminal and returning causes the display to activate, whereupon things function as expected.
I'll try to file a separate report tomorrow with reportbug unless informed otherwise. -Ben
