I have installed Ubuntu 11.10 64-bit on my Dell Inspiron N7010 .
When I'm away, the screen locks itself out and the screen goes black. However, when I move the mouse or press any keys it doesn't come back up or show me the lock screen dialog that should appears... it stays black.
Once I type in my password and then press Enter, it logs in but still remains black and I have to increase brightness to see my screen every time.
This happens every time the screen locks when I'm away.