I have been having this exact same problem since 8.04. I still have this problem with Karmic after installing from scratch. I did not try your fix above however.. its only happened to me once.. i always leave my system on.. it happened to me this morning. Usually always after about 8 or 9 hours of the system not being used.
nvidia 8600 GTS Asus P5K-VM nvidia non-free 185 2.6.31-14-generic kernel -- Dual Monitors won't SLEEP in TwinView mode https://bugs.launchpad.net/bugs/275308 You received this bug notification because you are a member of Ubuntu Desktop Bugs, which is subscribed to gnome-power-manager in ubuntu. -- desktop-bugs mailing list desktop-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/desktop-bugs
