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Installed Ubuntu 16.04 on ASUS laptop, everything worked except fn keys. Cannot mute/increase/decrease volume (f10, f11, f12) or increase/decrease screen brightness (f5, f6).

In troubleshooting I found people have similar issues regardless of machine (ASUS, ACER, Dell) or Ubuntu version, anywhere from 8.0-16.04

How do I fix this?

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  1. Edit GRUB config file to pass a kernel boot parameter

    • Open Terminal
    • type sudo -H gedit /etc/default/grub
    • Find this line: GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"
    • Add acpi_osi= immediately following quiet splash to give: GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_osi="
    • The next line should look like this: GRUB_CMDLINE_LINUX=""
    • SAVE and CLOSE file
    • In terminal, type sudo update-grub
  2. Create .CONF file

    • Open Terminal
    • type (or copy/paste): sudo -H gedit /usr/share/X11/xorg.conf.d/20-intel.conf
    • Enter this in the file line for line:

      Section "Device"
      Identifier  "card0"
      Driver      "intel"
      Option      "Backlight"  "intel_backlight"
      BusID       "PCI:0:2:0"
      EndSection
      
    • SAVE and CLOSE file

  3. Reboot computer

The above steps fixed my problem and I was able to use the function keys to control brightness and volume on my machine. I tried several things and edited the GRUB file several times, updating and rebooting every time. Some threads suggested edited the BIOS, others suggested installing xbacklight. It took a while to troubleshoot. If my solution doesn't work for you, here are threads that helped me:

  • I would add a link to askubuntu.com/questions/28848/… or redsymbol.net/linux-kernel-boot-parameters – lrkwz Nov 13 '17 at 22:12
  • This is great thanks, added to resource list – Kelly Dec 1 '17 at 18:02
  • The 20-intel.conf file fixed my issue, but the grub changes caused my splash screen to not show up and broke the trackpad. Reverted that and kept the .conf file, and everything is perfect. – Jacob Aug 9 '18 at 0:56
  • On my laptop (Sony VAIO PCG-4K1M running Lubuntu) just the GRUB part was sufficient to make it work. The brightness changes in small steps, so I needed to press multiple times to see it work. – Paul Mar 9 at 15:31

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