How to play with Ubuntu brightness Fix the fixed brightness If you have faced the problem of fixed brightness of ubuntu then you are at the right place because after searching so much, i have finally found the solutions. Yeah you are right, solutions..! There are so many causes to this problem thats why i have listed the possible solutions.You can try each and every solution and do a reboot after applying solution. Solutions Run this code in the terminal. xrandr --output LVDS1 --brightness 0.5 (It will not change the brightness but only the contrast. Also there is no need to reboot) Editing Grub Configuration Run this command sudo gedit /etc/default/grub . It will open the grub file. Change this code B_CMDLINE_LINUX_DEFAULT="quiet splash" to B_CMDLINE_LINUX_DEFAULT="quiet splash acpi_backlight=vendor" OR (try the first one then second if first didn't work) Change this code B_CMDLINE_LINUX_DEFAULT="quiet splash" to B_CMDLINE_LINUX_DEFAUL...