Hi all.

(Main) PCIe ATI Radeon HD 6850 with 2 DVI connectors
(Auxiliary) Integrated Intel HD Graphics 2000 with 1 DVI connector
Ubuntu 12.04

I'd like to have one desktop scattered over three monitors. Now I have it only at two monitors connected to (Main) card, configured by default. The third one doesn't show any picture.

How should I configure xorg.conf? Is it possible to have one "Screen" section with two "Device" entries? It really would be great if X could tie both devices to serve just one common "Screen".

First step I've tried to configure two screens - one existing and one for the third monitor at (Auxiliary) card. With such a configuration X does not start up (and due to this the PC as well, so at the moment I cannot show the xorg.conf I had nor Xorg.x.log files).

So the question is what approach in general is most correct to make Ubuntu use all the three monitors? If it is X that should be configured then how would it be configured? And if it is not (maybe not only) then what else should be done for achieving the aim?

Thank you.