12.1 / KDE: Triple Monitor on two graphic cards with nouveau instead of NVIDIA?

Hello fellow openSUSEians,

I am running a triple monitor setup on a computer with two NVIDIA 9500 GT graphic cards on openSUSE 12.1 with KDE.
These graphic cards come with 3 display connectors: 1x HMDI, 1x DVI, 1x DSUB (“VGA”).
My setup is as follows:

[li]graphic card 1:[/li][LIST=1]
[li]HDMI 1: Montor 1[/li][li]DVI 1: <none>[/li][li]DSUB 1: <none>[/li][/ol]

[li]graphic card 2:[/li][ol]
[li]HDMI 2: Montor 2[/li][li]DVI 2: Montor 3[/li][li]DSUB 2: <none>[/li][/ol]

I have installed the proprietary, closed source NVIDIA drivers and via “nvidia-settings” I am able to access both graphic cards and configure my 3 monitors very nice and easily. Everything works out of the box and is very configurable. So far so good. :slight_smile:

But: I would prefer running the open source driver nouveau, instead of the closed source NVIDIA drivers. :\

My problem is, that when I run nouveau, I don’t know how to access and configure the graphic card 2:

I tried to configure the multi monitor setup via the KDE settings, but there I can find only graphic card 1, thus KDE runs only on Monitor 1. Monitor 2 and 3, which are connected to graphic card 2, are not accessible via the KDE-settings.
Of course, when I plug e.g. monitor 2 to DVI1, the monitor appears in KDE settings, too, and I can configure a dual monitor setup. But since i want 3 monitors (and each graphic card can handle only 2 monitors), I need that second graphic card, too!

I have tried to find how to access the second graphic card, but there seems to be a lot of confusion going on due to SaX2 not existing anymore, xorg.conf being depreciated (?), etc. so most how tos are not current anymore.
Generally I can not figure out how to configure graphic cards in openSUSE anymore… In older times that was done with SaX2 or manually by editing xorg.conf. But how is it done today, since these things seem to have been eliminated??

Can anybody tell me how to do the trick to get the second graphic card up and running with nouveau?

Thank you for any feedback / hint / tip, etc.!

Best regards,

You’ve bumped into a current limitation of X in regards to its ability to handle multiple discrete video adapters.

With the nouveau driver you’ll have to either:

  • set up Xinerama … which will allow you to have one big desktop which you can move windows across … though there are several (limiting) drawbacks to Xinerama (acceleration etc.,)


  • set up a separate X window session … which will allow you to use all 3 monitors, but you won’t be able to move windows across to or from the third monitor (as its a separate session)

If I’m not mistaken, the nvidia "TwinView/Surround/whateveritscalled’ (under Linux and likely other OS that run on X) is their own version of Xinerama, tailored and hacked to work with their prop driver.

Lastly, as a more drastic option, you could still use three monitors contiguously if you upgraded to a newer video adapter that supported tri-monitor display. The benefit of this would be that you could use XRandR and, as well, not be precluded in your daily usage by the limitations of Xinerama.

Hello Tyler K.,

thank you for helping me!

Ok, I think I will stick with the NVIDIA driver then, since already with this one I am having limited performance, e.g. when dragging a window from a monitor of graphic card 1 to a monitor on graphic card 2 (noticeable stutter / lagging) or when maximizing a window (latency / delay). Concerning the drawbacks of Xinerama, here I found some additional information: https://en.wikipedia.org/wiki/Xinerama#Known_problems
Maybe at a later point I will set up a second test system with which I will experiment with nouveau and Xinerama. In this case I would come back an report my experiences here, since it might help other users, too. There are not all to many sources of information concerning multi-monitoring with more than 2 monitors available, unfortunately… (which is IMHO kind of strange if someone has a look at today’s low monitor prices, compared to some years ago and the tremendous increase of productivity and possibilities that you get with multiple monitors. …)

Thank you for this additional information. Unfortunately this is not an option for me, since the merging all 3 monitors to a united desktop is, what I need.

Yes, this is surely the best thing that someone can do today, at least if he wants to stick to maximum 3 monitors. At the time that I got my hardware, triple-head graphic cards still where not available unfortunately, they marketed shortly after. But for now I am not willing to buy new hardware just for this. But the next graphic card upgrade will surely be such a card. This way I will also free another 2 slots (since the graphic cards occupy 2 slots each due to the huge passive coolers that my cards have).

Do you know if nouveau supports such triple-head graphic cards already in a stable and productive grade manner?

Thanks for your time and effort for helping me!


Sorry, I can’t speak from experience in regard to this specific question … fwiw, I can’t foresee any reason why it wouldn’t … but instead of taking this monkey’s opinion, you could always check on the nouveau mailing list to get some confirmation :smiley: .

I haven’t use the nouveau except wen I install the openSUSE iso.
If you have the packman repositories in yast or zypper you can install the nvidia-settings and try if it will work.
do a search of nvidia in yast2 if you have the packman repo and you will find nvidia tools.

Me thinks you did not read rootpower’s post very closely.:stuck_out_tongue:

I stand corrected: You can move windows across the sessions by using Xpra - Wikipedia, the free encyclopedia (see the “See also” section for some other possible solutions too). Haven’t tried it yet but will test it out soon when I get a chance.

3 years on … i am stuck with the same problem …getting two nvidia cards ( 1 discrete , 1 built in ) working … any ideas ? anyone ?

Ok I don’t think that the nouveau driver supports SLI configurations you must go with the proprietary driver if you wish to use that configuration. I suspect there is patented tech involved thus the OS driver can’t use it legally

Use xrandr:

You can check that the basic requirement is met (i.e. see the relevant section of “man xrandr”) with:

 xrandr --listproviders

if that is indeed the case (which is more then likely), then issue:

xrandr --setprovideroutputsource 1 0 

After that you should be able to turn the additional monitor on via xrandr itself or through a frontend to it … try using kscreen (if you’re running KDE), as it should be self evident.

And then after that, setup the above setprovider line in a startup script (you can do this many different ways) so that its all evoked automagically each time you boot.

PS - I did not bother to review what the “same problem” was, but just jumped straight to the assumption that what I posted is what you’re after