Ask Ubuntu is a question and answer site for Ubuntu users and developers. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I installed Ubuntu and KDE too on my MacBook Air 4,2, but I realised I cannot change brightness in KDE. In Unity, it works without problem. Other keyboard keys works properly, sound, play, etc., but I cannot change brightness in KDE. I tried KDE4.8.4 and KDE4.9 beta. Thx

share|improve this question

I have laptop brightness buttons working. If I wouldn't I'd play with


files (do You have them - or some similar files there?). See what is written there - some shell commands.

Also in the old days bright could have been controlled with:

echo -n 100 > /proc/acpi/video/VGA/LCD/brightness # sets br to 100%

but now the mechanism is changed.

share|improve this answer

Your Answer


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.