Brightness should be controlled by pressing Fn + F5 and Fn + F6. Nothing happens when I press these keys. My computer is a Asus X551MAV­-SX366GB and I'm using Lubuntu 14.04

  • This is a known issue with Asus laptops. This post helped me: askubuntu.com/questions/489247/… (I assigned another keyboard shortcut for xbacklight). – Takkat Oct 25 '14 at 19:43
  • Not working for me :-( – Carsten Oct 26 '14 at 8:39
  • Well, I can now adjust brightness in the system settings, but not through fn keys. – Carsten Nov 4 '14 at 18:53
  • After changing this in my /etc/default/grub: GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_osi=" I now kan use the Fn keys :-) It still starts out with full brightness. Are there any way to make the computer start up on a lower brightness level? E.g. like the one I left it with? – Carsten Nov 8 '14 at 13:42
  • xbacklight was not installed, so I had to install it first. It seems to word fine :-) – Carsten Nov 9 '14 at 7:55

Here is the summary of what I did:

  1. I created the file /usr/share/X11/xorg.conf.d/20-intel.conf as described here 13.10 Can't Adjust Dell Laptop Backlight:

    Section "Device"
         Identifier  "card0"
         Driver      "intel"
         Option      "Backlight"  "intel_backlight"
         BusID       "PCI:0:2:0"
  2. Then I changed one line in/etc/default/grub so it looked like this: GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_osi=" and ransudo update-grub` from the command line.

  3. Install xbacklight Install xbacklight if not already installed sudo apt-get install xbacklight. Then I put xbacklight -set 50 to autostart applications.

  4. Reboot

This worked for me.

  • Hmmmm. Not working with Xubuntu on the same machine :-( I see the indicator, when I press function keys, but nothing happens. – Carsten Dec 23 '14 at 8:17

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