Take the 2-minute tour ×
Ask Ubuntu is a question and answer site for Ubuntu users and developers. It's 100% free, no registration required.

My laptop is a DELL 3521 with dual graphic cards, which usually cause some problems, and I have switched off the AMD Radeon card.

Now, when I want to turn the brightness down by dragging the brightness bar in the "Brightness and lock settings" and I close the window, nothing changes, and when I open "Brightness and Lock Settings" again, the brightness bar turn back to its previous state!

So, is it something is the system or I did some kind of mistake?

share|improve this question
add comment

1 Answer

Try it once.. It has solved all problems about brightness! Including mine!!

  • Open terminal ( Ctrl+Alt+T ) and type:

    sudo gedit /etc/default/grub
    

    You will find this line in the new opened window: GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"

  • Change it to:

    GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_backlight=vendor"
    
  • Save and close the window and type this in the terminal:

    sudo update-grub
    
  • Restart your system..

share|improve this answer
add comment

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.