Is the screensaver actually running, or has it crashed? (Run ps auxw | grep screen) If it isn't running, can you get a backtrace of it after a crash?
-- unable to unlock screen; gnome-screensaver appears to hang https://launchpad.net/bugs/71254 -- desktop-bugs mailing list desktop-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/desktop-bugs