Comment 7 for bug 68950

I also encountered this bug. I ran gnome-screensaver --nodaemon --debug for a long time, and noticed that when the screensaver wasn't working correctly, the debug output includes lines like

[manager_maybe_start_job_for_window] gs-manager.c:207 (21:33:38): Not starting job because throttled

Prior to that, the throttle is being toggled on and off for a while, but it seems to get stuck for some reason.

If I restart gnome-screensaver with

$ killall gnome-screensaver; gnome-screensaver

then things start working again.