[Solved] Brightness on Asus X200MA

The Asus X200MA I use has an issue with brightness. When everything is detected properly on Linux, the brightness can’t be adjusted using the hotkey (Fn). After switching kernels here and there, it was still no use. My attempt was to download the latest kernel (kernel 3.18, 3.19) hoping all the drivers would be complete, but it turned out to still have no effect. My last attempt was to use the default kernel 3.13 from Linux Mint 17 and it turned out to work with a little modification.

To test whether the brightness can actually be changed, run echo 1000 > /sys/class/backlight/intel_backlight/brightness you must be root !

Modifications that must be made :

• Enabling acpi so the hotkey is detected (this is actually a bug) by adding acpi_osi= to /boot/grub/grub.cfg. Find the word quiet and add it after it, making it quiet acpi_osi=

• Actually Linux has already detected intel_backlight, but it’s confused about which one to use, between acpi_backlight or the built-in intel_backlight. Therefore, it must be forced to choose intel_backlight. Open /usr/share/X11/xorg.conf.d/20-intel.conf (if it doesn’t exist, create it)

Section “Device” Identifier “card0” Driver “intel” Option “Backlight” “intel_backlight” BusID “PCI:0:2:0” EndSection

Good luck