My goal is to achieve one huge X screen on three monitors and two graphics cards. I got a working solution without Xinerama (one X screen on front+right and one X screen on the left) but this of course won't let me drag the windows. Enabling Xinerama makes something really strange to the right monitor, just see the video: http://upload.nowaker.net/nwkr/xinerama-fail.3gp As you can see, it's almost working.
01:00.0 VGA compatible controller: nVidia Corporation G73 [GeForce 7600 GT] (rev a1)
07:01.0 VGA compatible controller: nVidia Corporation NV44A [GeForce 6200] (rev a1)
(PCI-E x16 and old 32-bit PCI)
My xorg.conf: http://wklej.org/id/554292/txt/
Using Ubuntu 10.10, amd64.
Nouveau package version 2.4.21-1ubuntu2.1.
Have you tried if you have any better luck with ZaphodHeads?
The option is listed in the nouveau man page, but unfortunately I do not have an actual example to show. It would be configured like the "classic" separate-SCREEN dual-head, added with ZaphodHeads options.
Thanks for your suggestion. I will google for ZaphodHeads examples and give it a try.
In meantime, let me provide some new insights.
Just after X start: http://upload.nowaker.net/nwkr/dualcard-xinerama-after-startup.jpg As you can see, everything looks OK! (I don't care the window popping up in the middle of two monitors) When I move the pointer on the front screen or left screen, everything is still OK. When I move the pointer back to the right screen, the story from the last video begins. Have a look: http://upload.nowaker.net/nwkr/dualcard-xinerama-fail-2.3gp
I believe something trivial is broken here. It's almost working - starts OK but moving a pointer to the right screen starts the fail story.
I will also take a look at the source - but I won't be too optimistic as I am a Java developer and don't really know the X or Linux stuff.
@Pekka, thanks for your suggestion. I first tried ZaphodHeads but got a message in Xorg.0.log that driver doesn't understand it. I updated all X-related packages to the newest versions from https://launchpad.net/~xorg-edgers/+archive/ppa and apparently it works.
The strange thing you saw on the video is gone.
I saw it just once - maybe for 5 seconds - after a day-long work.
That's acceptable. :)
My xorg.conf: http://wklej.org/id/555276/txt/
You may update your instructions at http://nouveau.freedesktop.org/wiki/MultiMonitorDesktop
I wrote it from scratch as I didn't find any examples on the Internet.
In my case, three Xineramed screens, nouveau > nvidia in terms of performance.
Windows maximizing works correctly.
More about my system:
Currently I'm not interested in 4 monitors environment but being here I just checked it. X doesn't start. First GPUs monitors only blink several times. I will report a new bug for this issue soon after I test more xorg.conf variations.
I changed the status to INVALID since it was already fixed on Git.
An already resolved four monitors problem is here: