Ubuntu – Screen backlight control for Asus G55V

12.04asusbrightnessscreen

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.

Best Answer

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

Installation

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
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