Reactivating the Backlight

Overview

Some people - particularly those using laptops - are encountering a problem where the screen brightness is too dim upon replacing Microsoft Windows with a Linux distribution as their main operating system. Although it affects all Linux distributions, the problem is actually due to the computer's BIOS settings. Certain hardware manufacturers have set it up so that if Windows is not detected running on their systems, the backlight is automatically disabled.

Reactivating the Screen Backlight

This problem can be easily fixed by ensuring that the GRUB bootloader re-activates the backlight. To do this, first open up your terminal, and enter the following command:

sudo sed "s/\(GRUB_CMDLINE_LINUX=\)\"\"/\1\"acpi_osi=Linux acpi_backlight=vendor\"/" /etc/default/grub -i

You will also have to enter your password to continue. Now enter the second and final command:

sudo update-grub

Once complete, close the terminal and re-boot your system for the changes to take permanent effect. A Youtube video tutorial is available here.