running 2 Xorg servers on a computer

Olivier Demengeon olivier.demengeon at
Mon Nov 13 04:21:30 PST 2006


A few months ago, i configure 2 X servers on a computer, 2 nvidia cards
6800 gt and one keyboard and mouse. (nothing to do with SLI, the cards
was'nt connect together).
Everything run fine, I could use the 2 X servers to do 3D rendering at
the same times (glxgears at 13000 on X :0.0 and X:1.0). I use to look
only at one display (:0.0, had only one screen).
Everything was fine, i keep the config file and after some 3D benchmarks
tests, i stop to use 2 cards.

Since a few day now, i try to work again with 2 graphics cards, but i
lose my xorg config with 2 working cards, so i write a new one.

My problems is that i doesn't work anymore, i can launch 2 X server, but
only one seems to run at once, i've to switch to them using crtl-alt-F7
and crtl-alt-F8, to see a picture, there is no way to look at the two
together (i use 2 screen and 1 keyboard and 1 mouse) .And only the
visible one give me good 3D performance.

I've read the xorg archives and found some threads in 2004 saying that
there is no way to launch 2 X servers at the same time because each X
block the PCI bus.
Do I have dream about my first bench or is it possible from some times ago.

I use a fedora core 4 with a 2.6.12 kernel, a 6.8.2 xorg and nvidia
driver. My xorg.conf is attached. I launch the X this way :
      X :0 -ac -layout L0
      X :1 -ac -layout L1
I require just information on the Xorg part (since you have nothing to
do with nvidia driver), to know if it's possible to launch 2 Xservers on
a computer with 1 keyboard and 1 mouse, if there is no more problems
with the sharing of the PCI-express bus. And also some advice for the
xorg.conf to configure the input, if needed for this case (i've read the
man a few hours).

Best regards,
olivier demengeon

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