Lenovo T410 nVidia Display Brightness in Linux Mint

Linux Mint uses opensource nouveau driver for nVidia graphics and works fine. There is no additional configuration needed. But if you use binary driver you may experience that brightness function keys do not work.

First of all make sure to run nvidia-xconfig in order to create xorg.conf. This step is optional if you use the driver installer. The installer provides a wizard where you can allow to create customized xorg.conf.

Edit /etc/X11/xorg.conf and add the following option to the Device section:

Section "Device"
    ...
    Option "RegistryDwords" "EnableBrightnessControl=1"
EndSection

You might have to restart X server to use new settings.