Multi-GPU and Multi-Monitor setup on Linux. Is this possible anymore? (Not single large desktop!)

Hello all,

In a nutshell:
I’m in need of setting up a few systems that have dual graphics card (Quadro M5000) and Dual monitor on each GPU.
Each GPU will have one monitor that will mirror the other attached to it. The two cards need not be an extension of each other (and likely shouldn’t be), as the only thing that needs to pass between them is the mouse cursor. No windows will be dragged from one to the other.

This used to be possible right out of the box. How do I do this now?

Detailed background:
Three of these systems are being utilized to create a panoramic display for a flight simulator. There are a total of 12 screens, but 6 are only used for display field generation while the other 6 are mirrored. This is because 6 displays are monitors while the other 6 are projectors, hence why each card will mirror one display. The monitors are used by a sys-op of sorts and the projectors are used to display the image around a flight cab for a flight simulator.

Each GPU on each system handles one section of the display field. IE: System 1, GPU 0 will display top left image. System 1, GPU 1 will display bottom left. This is why I’m not interested in a single large desktop composed of individual displays. Other software (X-Plane, NWarp, etc) is used to stitch the displays together into one image.

In the past, we would use NVIDIA-SETTINGS to create a Multiple X-Screen configuration for each system; XScreen0 (top renderer) and XScreen1 (bottom renderer). This used to work out of the box.

After much exploring on Google and even here, I’ve learned that Gnome3, XFCE4, KDE5 (maybe4 too?), and even MATE no longer seem to have support for this Multiple X-Screen configuration. Like so many other posts, with a newer Display Manager, the second X-Screen doesn’t display anything other than the X Window’s “X” mouse cursor.

What I have not been able to find is a solution. Mucking about with the xorg.conf file has proven futile. Various revisions of NVIDIA drivers has proven futile (which makes sense as it seems to be a display manager issue). For many other users with this issue, they wish to have a single large desktop comprised of all screens on all GPUs. But this is not what our configuration is after. Each GPU is required for graphical rendering of its own screen and need not worry about the other.

Is this something XRANDR is able to do? I’ve only briefly begun tinkering with it and would rather not waste time with it if it’s not possible. Is there some other configuration software I need to use? Start an additional X-Sessions attached to the secondary GPU?

I’m hoping that someone here will be able to help point me in the right direction / to the right tools / etc. I’d really rather not rebuild all these systems with Windows…

Thanks,

-Kirk

You can always start another window manager on the second Xscreen to make it available, e.g.
DISPLAY=:0.1 openbox &

While the newer, common DEs don’t support this, you can still set up your own session, e.g. running one instance of a simple WM (icewm, openbox, etc) on each Xscreen.

generix,

Thanks for the tip! I’ll start playing around to see if I can get this going.

In the meantime, do you happen to know off the top of your head some less common DEs that still allow NVIDIA-SETTINGS to configure this setup?

-Kirk

Full DEs: none. You really need to use simple window managers that don’t care for xrandr and allow running multiple instances under the same user.