I have Ubuntu 11.04 installed on a Lenovo Thinkpad T410 laptop with nVidia GT218 display controller. I am unable to adjust the display brightness. Pressing Fn-Home and Fn-End brings up the display brightness on-screen display and the indicated level increases or decreases as it should. But the actual display brightness does not change.
Earlier I was able to Ctrl-Alt-F1 over to a text terminal and then do Fn-Home / Fn-End to successfully change the display brightness, and then Ctrl-Alt-F8 back to the Gnome session with the new brightness. But after upgrading to 11.04 the psuedoterminals have disappeared.