Fix Brightness Control Not Working for Ubuntu 14.04 & Linux Mint 17

Two of the most prominent issue with Ubuntu 13.10 are brightness control and sound. We saw how to fix no sound issue in an older post. In this quick post, we’ll see how to fix brightness function key not working in Ubuntu 14.04.

This article was originally written for Ubuntu 13.10 but it is equally able to fix brightness issue in Ubuntu 14.04 as well as Linux Mint 17.

On my Dell Inspiron, using the function key to change the brightness did not yield any results. Brightness was at the maximum and my attempts to lower it went in vain.

It turns out, there are 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, is for Intel one. Let’s first find out what graphics/video card to do you have.

Find video/graphics card in Ubuntu and Linux Mint

Run the command below in terminal to know what video card is used for the backlight/brightness:

ls /sys/class/backlight/

As you can see, the output for me is dell_backlight and intel_backlight. An indicator that the graphics card in use is Intel. Another way to find out the graphics card would be to go in System Settings->Details->Graphics. You can see the graphic card in use.

If your graphics card is Intel, you can proceed with the fix below.

Fix brightness control issue with Intel card in Ubuntu 14.04 and Linux Mint 17:

Open a 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:

That’s it. I think it’s one of the must to do thing after installing Ubuntu 14.04. If it worked for you, you may also try some other small tweaks related to Ubuntu 14.04:

• Turn off Bluetooth by default in Ubuntu 14.04
• Fix missing system settings in Ubuntu 14.04
• Fix Unity Freezes After Login In Ubuntu 14.04
• Fix Flash player issue with Chromium in Ubuntu 14.04

Did it work for you? Let me know if you have questions or suggestions.