Multiple X screens with proprietary NVIDIA drivers

vida10 · 2018-12-27 05:02:12

I have a triple monitor setup with two GPU's. In nvidia-settings it shows my third monitor ( the one on the 2nd GPU ) as yellow and I don't know what that means other than that it might mean it is on a different X screen.

$ xrandr
Screen 0: minimum 8 x 8, current 5120 x 1440, maximum 32767 x 32767
DVI-D-0 disconnected (normal left inverted right x axis y axis)
HDMI-0 connected 2560x1080+0+360 (normal left inverted right x axis y axis) 673mm x 284mm
   2560x1080     60.00*+
   1920x1080     60.00    59.94    50.00    60.05    60.00    50.04
   1680x1050     59.95
   1600x900      60.00
   1280x1024     75.02    60.02
   1280x720      60.00    59.94    50.00
   1152x864      75.00
   1024x768      75.03    60.00
   800x600       75.00    60.32
   720x576       50.00
   720x480       59.94
   640x480       75.00    59.94    59.93
DP-0 disconnected (normal left inverted right x axis y axis)
DP-1 disconnected (normal left inverted right x axis y axis)
DP-2 connected primary 2560x1440+2560+0 (normal left inverted right x axis y axis) 598mm x 336mm
   2560x1440     59.95*+ 144.00   120.00    99.95    84.98    23.97
   1024x768      60.00
   800x600       60.32
   640x480       59.94
DP-3 disconnected (normal left inverted right x axis y axis)
DP-4 disconnected (normal left inverted right x axis y axis)
DP-5 disconnected (normal left inverted right x axis y axis)

$ xrandr --screen 1
Screen 1: minimum 8 x 8, current 1920 x 1080, maximum 32767 x 32767
DVI-D-0 connected primary 1920x1080+0+0 (normal left inverted right x axis y axis) 477mm x 268mm
   1920x1080     60.00*+
   1680x1050     59.95
   1440x900      59.89
   1280x1024     75.02    60.02
   1280x960      60.00
   1280x800      59.81
   1280x720      60.00
   1152x864      75.00
   1024x768      75.03    70.07    60.00
   800x600       75.00    72.19    60.32    56.25
   640x480       75.00    72.81    59.94
HDMI-0 disconnected (normal left inverted right x axis y axis)

I use Herbstluftwm but herbstluftwm doesn't recognize that third monitor because it is on a different X screen.

$ herbstclient detect_monitors -l
5120x1440+0+0

When I try and start a graphical application on that screen it throws an error

$ DISPLAY=:1 st
Can't open display

I'm guessing I need to run another instance of herbstluftwm for the other screen, unless someone knows how to move that monitor to the first X screen if it's possible. I've read this section about combining monitors into a virtual screen, but I don't know if it'd work across GPUs. Has anyone dealt with this before or knows if it's possible to combine the screens/let herbstluftwm see the screen/run a herbstluftwm instance on the screen? Thanks in advance.

Ropid · 2018-12-27 08:10:09

Check out the xrandr options "--listproviders" and "--setprovideroutputsource <provider> <source>". You can use "--setprovideroutputsource" to make it so your X screen is running on the first card, and the second card shares its monitor and displays the contents produced by the first card. After you've run "--setprovideroutputsource" the monitor from the second card should show up in the output of "xrandr" and you will be able to enable it.

You can read a bit more about this in the PRIME article in the ArchWiki. Look at the "Reverse PRIME" section in that article.

Last edited by Ropid (2018-12-27 08:12:55)

seth · 2018-12-27 08:18:05

Combining outputs across GPUs will requires BaseMosaic and xinerama, killing the randr extension (which might be a problem because quite some processes seem to unconditionally use it these days)
https://wiki.archlinux.org/index.php/NVIDIA#Base_Mosaic but iirc nvidia-settings should allow to configure this as well.

As for the error: Displays aren't screens, try "DISPLAY=:0.1"

Edit: @ropid, I'm more than unsure about output redirection on an actual multi-gpu setup because they usually provide no source inputs (at least I've not seen one)

Last edited by seth (2018-12-27 08:19:50)

Arch Linux

#1 2018-12-27 05:02:12

Multiple X screens with proprietary NVIDIA drivers

#2 2018-12-27 08:10:09

Re: Multiple X screens with proprietary NVIDIA drivers

#3 2018-12-27 08:18:05

Re: Multiple X screens with proprietary NVIDIA drivers

Board footer