Debian – Software adjustment of LCD monitor brightness in Raspberry Pi

debiandisplayraspberry piraspbian

This is my first post here. I'm at the beginning of the road called Raspberry Pi.

Is there any way of changing the gamma/contrast/brightness of monitor via Raspberry Pi?

My Samsung 960BF doesn't have any hardware adjustment, only a power button.

I tried using xbacklight and got error

"No outputs have backlight property".

gddccontrol also didn't work. Error:

I/O warning: failed to load external entity "/home/pi/.dccontrol/monitorlist"  
   Document not parsed successfully
   Probing for available monitors"

And nothing is happening.

I connected my monitor through DVI-HDMI cable. Maybe this is why it doesn't work?

I'm using Raspberry Pi B+ V1.2 with Raspbian.

Best Answer

  • One tool I have used successfully (not on a pi though), is xcalib from the package of the same name. You can use it to change the gamma, eg:

    xcalib -gc 1.1 -a

    You can repeat this. To cancel use

    xcalib -clear

    Another useful option is making the whole screen reverse-video:

     xcalib -invert -a

    It is intended to work with icc profiles, but I have only used the above commands.

  • Related Question