Triplehead config problem - one monitor stays black
 

Hey there,

I've searched a lot around this forum and other sources, but could not find anything helpful. If someone had an idea or a good guide that would be appreciated.

My Setup: 2x graphiccard (quadro fx 3400+quadro fx 3500) with 3 monitors (tft, 20") attached to 2x fx3500 and 1x fx3400) on linux ubuntu 8.04. All cards, monitors, cables are ok (switched primary card in bios, changed monitors).

I want to have all three monitors together in X as one display. I DON'T want high performance, 3d, compiz or other stuff, I have to work with it and only need some terminals, editors and rdesktops.

What I did: Install the nvidia driver, run nvidia-xconfig, then nvidia-settings. I select all three displays as own screens (no twinview since I have 3 monitors) and use Xinerama (checkbox in nvidia-settings). I save the config (no merge to have a clean config) and restart X, but the third screen (attached to the fx3400) stays black.

Althrough X sees both cards and all three monitors, it only processes the first two screens.
No Error and no warning, it's just ignored!

When I run nvidia-settings again, the third monitor is again disabled (see screenshot).

I have no more ideas. I've tried setup with twinview plus one screen, with different displays, changed the position and panning - no change.

I've attached the logs+config (bug report), does anyone have an idea? The setup worked on my old system, so there must be a way! As I said, I do not want any glx or high performance, just my three monitors!

Thanks and best regards
Eike

Re: Triplehead config problem - one monitor stays black
 

Which version of the Nvidia drivers are you using? Also, maybe you should try using version 9.04 once it comes out. I think I remember reading about a fix for multiple graphics card users in X.

Re: Triplehead config problem - one monitor stays black
 

Just tried Ubuntu 9.04 with the 173er, the 180er and the 185er driver. No change. I just cannot add any third screen.

Please help!!

Re: Triplehead config problem - one monitor stays black
 

Hi!

I couldn't find any obvious issues in the nvidia-bug-report.log, however the
following hints might be useful:

The log output of the X server says:

Some product spec says that the FX3400 has one Dual-Link DVI output and
one Single-Link DVI output. So it looks like you have attached the third LCD to
the SL DVI output. There's basically nothing wrong about that, because a
1600x1200 LCD should work with a single link connection, too, but for the sake
of completeness, you may try if using the other output on the FX3400 makes
any difference.

BTW.: I used to put the Option "Xinerama" "True" (rather than "1") into the ServerLayout
section (rather than into ServerFlags), but i guess it should work the way you have
it, too.

In the ServerLayout, it says:

That should work, but in case you once change the displays
with different resolution, then the fixed 1600 0 might be a problem.
I'd rather use this to make it independent from the screen
resolution:

There are metamodes defined in each screen section. You shouldn't
need them for your setup.

regards

Bernhard

Re: Triplehead config problem - one monitor stays black
 

Hi Jaxxon, thanks for the hints.

The config is actually generated by nvidia-xconfig, nothing changed manually, but I'll try your hints anyway.

Does anyone know if it's possible that the cards cannot work together? Could it help to try two similar cards?

What really bothers me is that there is no error/warning, it's just ignoring the third monitor whatever I do. It even disappears in the nvidia-xconfig every time. Strange strange...

Damn, I'm working with one black monitor on my desk for quite a month now. My productivity is only two-thirds right now ;)

Re: Triplehead config problem - one monitor stays black
 

The only limitation I'm aware of is that you need GPUs of the same family
for OpenGL. As per your log, the FX 3500 has a G71GL and the FX 3400
has an NV40GL. However, I once successfully ran UT2004 across three
screens using a 7800 GTX (G70) and a 6600 (NV40), so your setup
might work for 3D, too. Anyway, even if your GPUs are not similar enough,
2D should work across both cards and 3D should at least work for the two
LCDs connected to the FX 3500. As per README:

You have GLX enabled, but there is no such warning in your log, so I guess
the driver thinks your GPUs are similar enough for 3D operation, but doesn't
make use of the second card at all without any further notice ... very strange
indeed!

You may give it a try (I'm pretty sure it will fix the problem).


If it's urgent, you may also try a different solution that gets rid of the
annoying re-draw events when moving windows across screen boundaries
and will even allow you to run a composition WM and :

http://www.nvnews.net/vbulletin/showthread.php?t=106517

In this case, you could triple your productivity (from the current state)
with the following variant:

http://www.nvnews.net/vbulletin/showthread.php?t=126134
(check post #26)

regards

Bernhard

Re: Triplehead config problem - one monitor stays black
 

Hi Bernhard (are you german?),

first thanks for your help. I was busy last weeks but at least managed to get hold of another FX3400, so I could test having two equal cards in the system.

Does not work :(
Excactly the same behavior with two FX3400. I setup everything in the nvidia-settings, restart X and got only two screens. Running nvidia-settings again gives me (see screenshot) one monitor disabled. NO ERROR OR WARNING IN THE LOGFILE regarding this.

I am getting mad. What's wrong with me?

Btw., how does SLI come into multimonitor configs? I could try to build some SLI, since the FX3400 are SLI capable and also my workstation (HP xw9400).

I don't understand how this fits into my problem. I would love re-draw events if I only get the third monitor to work ;)

Wow!! That's nice!
But for working/coding I found for me 3 monitors as the maximum, one main in the middle and the outer two for output/documentation ;)

Best regards
Eike