The latest version of Ubuntu with long term support (LTS) 14.04 came out in April and users are starting to report minor problems. One of the issues is the problem of adjusting screen brightness on notebook computers. In this article, we report a solution for this problem.
This issue causes the screen to display blinding maximum luminance and controls have no effect. This is caused by bugs in this version of Ubuntu for Intel and nVidia video cards (see here).
This method fixes this issues for Intel integrated graphics, which is what is used in most of notebooks.
2. Edit and put the following into the
Section "Device" Identifier "card0" Driver "intel" Option "Backlight" "intel_backlight" BusID "PCI:0:2:0" EndSection
3. Save the file, log out, and log back in. The brightness controls should be working now.