Description of problem: Brightness keys (Fn+Home and Fn+End) don't work on a ThinkPad T61 with Nvidia Quadro NVS 140M. How reproducible: The keys don't work with nouveau and don't work with kmod-nvidia. Steps to Reproduce: 1. Hold Fn 2. Press Home or End Actual results: Nothing happens. Expected results: Screen brightness should change. Additional info: Echoing values between 0-15 to /sys/class/backlight/acpi_video0 works as expected. The keys send XF86MonBrightnessUp and XF86MonBrightnessDown as expected.
I think this is not xorg-x11 problem. AFAIK it is your desktop software who catch the brightness up/down events and controls the backlight through kernel interface, i.e. in Gnome it is the gnome-settings-daemon, in XFCE it is xfce4-power-manager. These daemons supports several interfaces. I think they prefer nv_backlight interface over acpi_video0 interface (if nouveau is used).
Okay, so what's the solution, I have the same problem here with F(17) latest updates up to this date.
I found something here: http://forums.fedoraforum.org/showthread.php?t=276516 to add Option "RegistryDwords" "EnableBrightnessControl=1" to the xorg.conf. It fixed my problem anyway.
My T61 is dead, so I'm closing this one, feel free to reopen, if someone else worry.