I have the following hardware configuration:
- PC running Ubuntu 10.04
- Onboard video card with one VGA output (Intel P4M800 - Via Unichrome)
- VGA splitter: 1 input, 4 outputs. Up to 2048x1536 (according to spec)
- One 42'' TV/Monitor connected to the splitter via its VGA input
- Two 32'' TV/Monitor connected to the splitter via its VGA input
With that configuration, Ubuntu only shows 640x480 and 800x800 as possible resolutions. However, if I connect any of the TV/Monitor directly to the PC (via VGA) then Ubuntu shows a long list of possible resolution (I tried several of them and they worked fine).
It seems that X Window System automatic configuration is not working properly. How do I manually configure it? What info should knows of the different devices involved beforehand?
Context: The monitors are intalled in public spaces across one building to display dynamic information that is processed in the PC (a Flash presentation running in Firefox in fullscreen mode).
I tried the following, as the link provided in the answers said:
Get the modeline for the resolution using
Created the new mode using
Added the mode to the output display using
Tried to change the resolution using
xrandr --output ... --mode ...
But I get this:
xrandr screen cannot be larger than 800x600 (desired size ...)