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!

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!

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!"

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!

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!