Ubuntu – How to change the screen brightness on Zenbook UX305 with media-buttons


The keys fn+F5 and fn+F6 do not change the brightness on my Asus Zenbook UX305.
I can change the brightness from the command line with this command:

xrandr --output eDP1 --brightness 0.5

This example reduces the brightness to 50% of the rather bright default on the UX305.

But how can I use the default keys (see above) to change the brightness?

Warning: Do not use a brightness value greater than 1.0. Damage to your screen or eyes may result.

Hardware: Asus Zenbook UX305, UX303UA, …
Ubuntu: 14.04, 16.04

Related: How to Enable Brightness Buttons in 16.04 of Zenbook?

Best Answer

  • I am having the same problem with the newer UX305CA. Apparently it is really common since the hardware is not recognized, so I just assigned a new shortcut. Following this answer:

    sudo apt-get install xbacklight

    Then assign new shortcut:

    • Settings > Keyboard > Shortcuts > Custom Shortcuts > +

    Add those two:

    • Brightness up: xbacklight -inc 10
    • Brightness down: xbacklight -dec 10

    Then click on each of the Disabled and select the new shortcut. In my case I used Alt+F5 and Alt+F6 (since I use Ctrl+F5 for web dev).

    If you want, you can also mess with the boot options to fix it:


    I have the same problem. there is a workaround although.

    add "acpi_osi=" at the and of the kernel boot parameters.

    to permanently do this edit /etc/default/grub as root and add "acpi_osi=" at the end of GRUB_CMDLINE_LINUX_DEFAULT then run "update-grub" as root

    after that brightness and all other hotkeys work but the ambient light sensor is no longer detected. But this is not a big problem since there is no standard ambient light regulation of screen brightness anyway