Configuring X for four monitors

[RandomJoe]

I did some searching, but didn't find anything that helped... But my "search skills" have left a lot to be desired in the past, so please feel free to point me elsewhere if I missed something! :D

I just purchased an ASUS P5N32-SLI SE Deluxe mobo and two MSI NX7600GS video cards (have dual DVI outputs and a 7600GS GPU). While SLI sounds interesting, my primary interest is three or four heads - can't get enough screen space! :) But I'm running into a brick wall getting both monitors on the second card to work - only the first one gets used.

The system is a Core 2 Duo E6600, 1GB RAM. I currently have Ubuntu 6.06 loaded, no customizations at this point.

I have been able to do the following to get both heads on the first card to work per the README file:
Section "Device"
Identifier "card1fp1"
Driver "nvidia"
BusID "PCI:1:0:0"
Screen 0
EndSection

Section "Device"
Identifier "card1fp2"
Driver "nvidia"
BusID "PCI:1:0:0"
Screen 1
EndSection

But if I replicate that for the second card, changing the appropriate lines (BusID becomes "PCI:8:0:0", I set the Screen lines to 3 and 4, and changed 'card1' to 'card2') I only get the first screen, and a line shows up in the X log reading something like:

No matching Device section for instance (BusID PCI:8:0:0) found.

The X log shows the nvidia driver does see both panels that are attached to the second card, but the second display is never used...

Any suggestions or especially a working example would be great!

I'm currently running just dual-head (one card), because I also had issues where the video would hang solid after a short period of operation with both cards in. I did find another thread that suggested trying "pci=nommconf" to fix that - I'll be doing that in a few minutes, but thought I would go ahead and post this problem as well.

Thanks!

[netllama]

I'd suggesting removing your current xorg.conf, and then running:
nvidia-xconfig -a --twinview --xinerama

If you need further assistance, please generate and attach an nvidia-bug-report.log.

Thanks,
Lonni

[RandomJoe]

First, the really good news - "pci=nommconf" eliminated the video lockup problem, that bit's just fine! :D

Next, running the nvidia-xconfig line you mentioned does generate a file that runs all four screens. With a couple of issues - not sure if these are things I can configure around or not:

I have one 19" FP that I want in the center of three panels. There are two 17" FPs that flank it. I was going to put the 19" on the first card, and the two 17"s on the second, but I don't think I can split the TwinView screen around the center panel?
The two monitors that were on the first card had the menubar stretched across both screens - as I expected, since X sees it as a single large monitor, although I would prefer to keep it only on one panel. When I would maximize apps they went "fullscreen" across both panels as well. Can that be accounted for somehow?


Related to that first, is it even an issue whether I have one of the side panels on the same card as the center? I was thinking perhaps I'd get a little better performance if it was by itself, but what I have right now is so much better than anything else I own I probably wouldn't miss it...!

When not using TwinView, I do now have a working three-panel config, which is satisfactory although I would certainly like to get the fourth output usable. By putting just one monitor on the second card, X picks it up just fine. It's only when I add the second Device section for that card that it says "No matching Devcie section for instance (BusID PCI:8:0:0) found".

Thanks for the help! The bug report log when trying to run a quad-display non-TwinView setup is attached.

[RandomJoe]

*smack*

"When in doubt, READ THE DIRECTIONS!" :p

Not sure why, but I finally got around to reading the xorg.conf manpage. And found out I've been doing it wrong... My second card's Device configs should have been:
Section "Device"
Identifier "card2fp1"
Driver "nvidia"
BusID "PCI:8:0:0"
Screen 0
EndSection

Section "Device"
Identifier "card2fp2"
Driver "nvidia"
BusID "PCI:8:0:0"
Screen 1
EndSection
Note that the Screen numbers are 0 and 1, exactly the same as for the first card, not 2 and 3, as I was doing. I was getting confused by the fact that later on, in the ServerLayout section, I do use Screen 2 and Screen 3 to identify them there. Silly me, I assumed the two sections' tags correlated! But the Device section's 'Screen' must be 0 to one less than the number of heads on that device (or "entity" as the manpage calls it).

So, now I have all four monitors stretched across the desk in one huge Xineramic display! :D

Only problem I'm having now is Unreal Tournament (perhaps others but it's the only one I've tried so far) - if I have the screens in Xinerama mode, when I run UT the game window appears full-screen on the display I started it, but a blank window with the title "Unreal Tournament 2003" also appears on one of the other displays. And the mouse is nowhere to be found! If I disable Xinerama (of course, getting a separate desktop per display) the game runs properly.

Thanks again!