3x2 video wall with BaseMosaic, treat as single display?

Apologies if this is not the right forum topic for this…I was torn between the “Mosaic” topic and “Linux”.

I am configuring a 3x2 video wall using BaseMosaic on a RHEL 7 box running GNOME with dual Quadro P4000 cards. I have the displays oriented correctly, but I can not get GNOME to stop treating it as 6 individual monitors. For the primary application I will use on this system, I need full-screen/maximize to go across all 6 screens.

I have been following the guidance here: https://nvidia.custhelp.com/app/answers/detail/a_id/3580/~/how-to-configure-mosaic-on-linux. I have nvidiaXineramaInfo set to FALSE, but it seems that GNOME is still using XRandR, which this page mentions as a possibility. When I disable the “Composite” Option, as indicated, GDM doesn’t seem to start. I get no login screen…just a blank screen with a mouse pointer.

Is it possible to make GNOME treat these displays as one 5760x2160 desktop? Do I need to switch to a different WM? Or…can I make GDM work properly with RandR disabled?

Any help would be appreciated!

Matt

You might try using the randr 1.5 monitor feature:
E.g., for two displays, use
xrandr --output DFP-1 --auto --right-of DFP-0
xrandr --setmonitor virtualmonitor auto DFP-1,DFP-0

I switched to Openbox, and it is giving me the behavior I want.