Install armada-backlight by entering the following commands in the terminal:
sudo apt update sudo apt install armada-backlight
Description:
adjust backlight of Compaq Armada laptops (E300, M500, M700)
An utility to change the laptop LCDs backlight from a command line. The brightness can be adjusted in steps for Compaq Armada family of laptops (E300, M500, M700).
Version: 1.1-9
Section: universe/utils