[Linux] How to Enable Backlight Control and Fix Most Function Keys on Laptops


1. As root, edit /etc/default/grub and find the line begining GRUB_CMDLINE_LINUX_DEFAULT=

2. Add the commands acpi_backlight=vendor to the end of this line and save the file.

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_backlight=vendor"

Adding acpi_osi=Linux allows the laptop’s function keys to work for backlight control but will likely introduce some power drain issues.

Thus the line would look like:

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_backlight=vendor acpi_osi=Linux"

3. Run the command update-grub to rebuild the boot configuration.

4. Reboot. You should find you keyboard backlight controls work only when acpi_osi=Linux is included.

One thought on “[Linux] How to Enable Backlight Control and Fix Most Function Keys on Laptops”

  1. I realize this article is pretty ancient but the laptop-mode-tools should have more function and be able to curb the increased battery drain as a result of acpi_osi=Linux. It basically just reveals more ACPI control to the kernel. The kernel defaults basically just prefer max performance, tweaking the settings will net you similar battery life as without the option enabled.

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