I installed Ubuntu 16.04 recently, and had a problem with the Fn+F5 and Fn+F6 keys on my Asus K401UQ not changing the screen brightness. I tried the methods that were posted on different forums, about editing the grub configuration file.

  1. Original Configuration - quiet splash - The keys don't respond, but brightness can be adjusted through software(and settings).

  2. Added acpi_osi= at the end,now the brightness keys respond and the onscreen brightness bar appears and changes, but no actual change in brightness. Software based control is lost.

  3. Added acpi_osi=none, acpi_osi=vendor etc, nothing works.

I have Intel HD Graphics 520 and Nvidia 940MX, currently using Nvidia driver software to toggle between both cards(No change even on nvidia card). Also tried default Xorg noveau driver. All the solutions Ive read over the past month don't seem to work. Thanks!

  • Last resort (nothing else works for me either): Changing Screen Brightness Through Keyboard Functions on My Notebook – Zanna Jan 28 '17 at 8:16
  • I set a keyboard shortcut as a temporary measure, but wished there was proper workaround! I still have to use some other combination other than the default Fn+F5/F6, but, something's better than nothing! Thanks! – Gman007 Jan 29 '17 at 9:40
  • I generally use acpi_osi=! on ASUS but that shouldn't change compared to what you're using. That said I normally have additional ACPI parameters for backlight which might have farther reaching impact than I'd expect. – Ginnungagap Feb 1 '17 at 23:03
  • Also, if you just want to test options, you can use e in GRUB at boot time to temporarily edit an entry before starting it :) – Ginnungagap Feb 1 '17 at 23:05
  • 2
    Possible duplicate of Changing Screen Brightness Through Keyboard Functions on My Notebook – Zanna Apr 25 '17 at 13:48

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