Since there us a defect in my laptop screen, I am using an external Dell 1600x1000 monitor. Windows was recognizing the native resolution correctly. But when I installed Ubuntu 10.10, I get only up to 1024x768 in the Monitor preferences. I had a look at this and tried to add resolution by running

xrandr --addmode VGA 1600×1000

but I am getting the error

xrandr: cannot find output "VGA"

What is the way out.

  • What is the output you get from running just xrandr? ("$xrandr") – Shuaib Apr 3 '11 at 12:45

Try to run xrandr and check that the output name is indeed VGA. Sometimes it will be VGA1. If you don't see VGA nor VGA1, it might be because your X configuration and/or X video driver were really unable to detect or enable the VGA output.


I've run into this on several machines. There are many web hits for this issue, so apparently many others are having the problem, but very few with correct and complete information. Usually it is necessary to add a suitable mode, which requires the "cvt" utility to generate the "modeline". Useful web pages include:

UbuntuGeek on using xrandr with GDM and vr-zone on using xrandr with ~/.xprofile.

You can probably find others with a search that includes "xrandr", "cvt", and "modeline".

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