Ubuntu: Screen backlight control for Asus G55V


I've just installed Ubuntu 12.04 on an Asus G55V laptop and neither the laptop brightness control keys (FN+F5, FN+F6) nor the Brightness setting are able to control the backlight.

Note that I've installed the nvidia-current driver, as the laptop is equiped with a GeForce GTX 660M, and it's working fine.

So far here is what have tried to no avail:

  • Switch to a console (Alt+F1) and use the laptop brightness control keys (this method was working with 10.04 and Lenovo T410),
  • echo 2 > /sys/class/backlight/acpi_video0/brightness,
  • Added GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_osi=Linux acpi_backlight=vendor" to /etc/default/grub and updated Grub config,
  • Also tried without acpi_osi=Linux.

Out of all these attempts, one thing changed: if I change the brightness in the BIOS bootloader right before booting on the HDD, the brightness setting stays the same in Ubuntu. This is an acceptable temporary workaround but I would really like to be able to control the backlight brightness from Ubuntu (can be from command line, fine with me).

Any suggestions on what to try next would be highly appreciated.


Try with: https://github.com/guillaumezin/nvidiabl


wget https://github.com/downloads/guillaumezin/nvidiabl/nvidiabl-dkms_0.76_all.deb  sudo dpkg -i nvidiabl-dkms_0.76_all.deb  sudo modprobe nvidiabl  

Print current brightness value

cat /sys/class/backlight/nvidia_backlight/actual_brightness  

Print maximun brightness value

cat /sys/class/backlight/nvidia_backlight/max_brightness  

Adjust brightness

echo 50 | sudo tee /sys/class/backlight/nvidia_backlight/brightness  


try to execute the following command:

/usr/lib/gnome-settings-daemon/gsd-backlight-helper --set-brightness 3

replace 3 with something between 0 and max-brightness. You can find out what max-brightness is by running following command:

/usr/lib/gnome-settings-daemon/gsd-backlight-helper --get-max-brightness


I had similar problem with Asus P50IJ notebook and Ubuntu 14.04. After i add the kernel boot parameter "acpi_backlight=vendor" the function keys works again.

You can use this command:

 sudo sed -i 's|quiet splash|acpi_backlight=vendor quiet splash|g' /etc/default/grub   sudo update-grub  

Don´t forget to reboot you notebook after that.


Try this It just might work as long as the keys are ACPI ones... Personally, I still get: "failed to find any devices" but still working on it...

Note:If u also have question or solution just comment us below or mail us on toontricks1994@gmail.com
Next Post »