Brightness automatically goes to full whenever I log in

Question

Whenever I log in to Ubuntu, the brightness automatically goes to full. I'm using ubuntu 20.04 LTS with dual boot.

Any solution for this?

Answer 1

This can often be fixed by adding a setting to your Grub configuration. Try this:

1. Open Terminal (if it is not already open)

2. Edit the Grub configuration file:

   $ sudo vi /etc/default/grub
   

   Note: Feel free to use any text editor you prefer, so long as you are editing the file with sudo.

3. Find the line that starts GRUB_CMDLINE_LINUX_DEFAULT and add acpi_backlight=vendor. This should give you a line that looks similar to this:

   GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_backlight=vendor"
   

   Note: Your line may be longer with additional settings if you have an Nvidia video device or other hardware.

4. Save the file and update Grub:

   $ sudo update-grub
   

5. Reboot.

This should resolve the issue.