Fix the brightness function keys on Ubuntu
If you’re running Ubuntu with discrete graphics on a Thinkpad T530, it’s most likely that the brightness function keys don’t work.
This happens when you’re using the proprietary Nvidia driver.
Luckily, this is easy to fix by adding one line to the /etc/X11/xorg.conf configuration.
Generate the xorg.conf
First see if the /etc/X11/xorg.conf file exists.
If not, you can create the file as follows;
$ sudo nvidia-xconfig
Add the configuration option
Then, add the following line within the Device section (search for Section "Device")
Option "RegistryDwords" "EnableBrightnessControl=1"
That’s it! After reboot or logout/login your brightness functions keys should work again!