I am also having this problem with Ubuntu 11.04-64 bit on an HP dm1z and Catalyst 11.5. Trying to sleep or hibernate causes the screen backlight to stay on, and the system to lock up, requiring a hard reset to get out of it.
I am also having this problem with Ubuntu 11.04-64 bit on an HP dm1z and Catalyst 11.5. Trying to sleep or hibernate causes the screen backlight to stay on, and the system to lock up, requiring a hard reset to get out of it.