I have to setup an X server on a linux station that can export its display (the whole session + gnome) to an external display which has a huge resolution (it's a wall of screens). The resolution is about 9000x4000.

Naturally, the video card on the server doesn't support this. I was thinking of creating a secondary X server with a custom/dummy video card that is used only to export X through XDMCP and render the output on the remote X server which runs on the display controller (and supports this resolution).

My question is - how do I setup this "dummy" X server? Is the max resolution provided by the video card a limit for the resolution of the server?

I remember in the old days one could setup a virtual resolution for the X server of let's say 1024x768 and a real resolution of 800x600 and the screen would automatically pan to fit the 800x600 resolution. I'm hoping I can use the same trick this time, but I need a push in the right direction.


  • You may want to check out this question. superuser.com/questions/71794/… – Zoredache Nov 18 '09 at 7:35
  • Thank you for your suggestion Zoredache, but that post isn't helping. I already have a huge X server running on the screen controller. I just want to export the desktop from a smaller X server to the big one - and take advantage of the bigger screen size. – Mad_Ady Nov 18 '09 at 7:52
  • X does not directly support to "export the desktop from a smaller X server to the big one". Each server has to start its own desktop. You might however want to investigate VNC or you need this. Also see my answer. – sleske Nov 18 '09 at 9:46

You are mixing up your terminology (which is admittedly confusing with X). The X server runs on the maching that has the display and the videocard, i.e. in your case the X server would run on the machine that has the video card for the wall of screens.

You configure the X server on that machine (how will depend on the video card etc.). Then the computer where the actual software (Gnome etc.) runs on will need to offer XDMCP or similar, and allow you to login. This computer should not care about the X server's resolution, as it only runs the individual X programs (including the WM). The X server must be started so that it automatically connects to the XDMCP server (command line parameter with X.org).

Just out of interest: What kind of video card supports 9000x4000?

  • Thank you for the extra information. There are 27 video cards which make up the wall of screens - so its a composite resolution. So - to get things straight - I shouldn't set up a secondary X server, I should just 'export DISPLAY=remoteIP:0.0' and then start gnome - right? I'll give it a try :) – Mad_Ady Nov 19 '09 at 7:34
  • @Mad_Ady: Yes, that should work. More elegant would be to set up XDMCP, but in your case it's not really necessary. It might help if you want to choose between sessions on different hosts. – sleske Nov 19 '09 at 10:42
  • Yes, it worked beautifully! Thank you for your help! – Mad_Ady Nov 19 '09 at 11:02

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