“Fails to get size of gamma” error when trying to set resolution

Question

On 11.10 my max allowed resolution is 1024x768, while my monitor supports 1280x800 on windows.

I've seen a method to solve this via xrandr, but I allways get a message saying it fails to get size of gamma.

 xrandr: Failed to get size of gamma for output default
Screen 0: minimum 640 x 480, current 1024 x 768, maximum 1024 x 768
default connected 1024x768+0+0 0mm x 0mm
   1024x768       61.0* 
   800x600        61.0  
   640x480        60.0  

Is there any other way to add 1280x800 resolution to my laptop, any workarounds this?

Thanks in advance.

Answer 1

You need to add a modeline in your Xorg.conf file. Please read this: http://www.x.org/wiki/FAQVideoModes The part about powerstrip may be interesting as you have windows running with the correct resolution.

Answer 2

I noticed your maximum resolution shown in xrandr was limited to 1024x768. Maybe FIRST you may follow the wiki below and try forcing X to recognize the video RAM.

Not recognised video cards

i.e. putting new lines in /usr/share/X11/xorg.conf.d/99-vesahack.

After the max is successfully changed after a reboot, you may proceed to next steps, for example --newmode and --addmode, etc.

I happened to have this problem during the debugging of my ivy bridge. I think this might be the reason of your "Failed to get size of gamma" error.