Using 12.04 on an Acer Aspire V5-561-9410. When I use the function keys to modify screen brightness (or use any solutions I've found here to this problem like the one found here or here), I see the brightness bar appear and change in the top right of my screen, but my actual screen brightness doesn't change. Does anyone know of a fix for this? I'm assuming it's a related issue, but I also don't see any change in screen brightness when going from running on AC power to running on battery.

1 Answer 1


This may not be the most modest approach, but it works for my Ubuntu 12.04 Acer.

You will need to run this command as super user (su).

$ sudo su
# echo 200 > /sys/class/backlight/intel_backlight/brightness

This will change your brightness (on a scale of 0-1000). Be careful you don't put in 0 or your screen will turn off!

If this process works for your machine, it's not too difficult to write a short script that macros the command to your keyboards shortcut keys.

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