One of the most well-known issue of ubuntu is its function keys not working to control the brightness of the screen. In this issue we’ll see how to fix brightness issue of not working of function keys.
On my ACER Aspire, I was using the function keys to change the brightness but it was not showing any results. Brightness of the screen was at the maximum and I was trying to lower it but it showed no change.
Note: This article was originally written for ubuntu 14.04 but it is also working for Ubuntu 15.10 or ubuntu 15.04
There can be two bugs related to brightness issue in Ubuntu. One relates to Nvidia Graphics Card and other relates to Intel Graphics Card. The solution that worked for me was with the Intel Graphics Card.
Find graphics card in Ubuntu and Linux Mint
Run the command below in terminal to know which graphics card is used for the brightness:
So, as you can see the output for me is acpi_video0 and intel_backlight. The indicator shows that my graphics card in use is Intel Graphics Card. An alternate way to find this out is going to System Settings -> Details -> Graphics.
If your graphic card is also Intel then you can go with the following fix and get rid of the problem:
Fix brightness control issue:
Open terminal and create the following configuration file, if it does not exist:
sudo touch /usr/share/X11/xorg.conf.d/20-intel.conf
Now we need to edit this file. You can use any editor be it a terminal one or graphical.
sudo gedit /usr/share/X11/xorg.conf.d/20-intel.conf
Add the following lines to this file:
Section "Device" Identifier "card0" Driver "intel" Option "Backlight" "intel_backlight" BusID "PCI:0:2:0" EndSection
Save it. Log out and log in back. The brightness control should be working through function keys now.