Bdtyktl

Installed another gpu (Nvidia 710) with intent to drive three screens for Ubuntu Host, and use existing gpu (Nvidia 1080) as a Windows Guest pass-through.

This machine does not have integrated graphics.

All three monitors get signal when plugged into only the 1080.

All three monitors show "No Signal" when plugged into only the 710.

For testing purposes, all three screens are plugged into both cards.

This configuration works as intended in Windows 10, and each card functions correctly by itself.

Checking what linux sees:

$ lspci | grep VGA

0b:00.0 VGA compatible controller: NVIDIA Corporation GP104 [GeForce GTX 1080] (rev a1)

0c:00.0 VGA compatible controller: NVIDIA Corporation GK208 [GeForce GT 710B] (rev a1)



$ xrandr

Screen 0: minimum 8 x 8, current 6000 x 2160, maximum 32767 x 32767

DVI-D-0 disconnected (normal left inverted right x axis y axis)

HDMI-0 connected primary 3840x2160+1080+0 (normal left inverted right x axis y axis) 1080mm x 610mm

   1920x1080     60.00 +  59.94    50.00    29.97    23.98    60.05    60.00    50.04  

   4096x2160     59.94    50.00    24.00    23.98  

   3840x2160     59.94*   50.00    29.97    25.00    23.98  

   1680x1050     59.95  

   1600x900      60.00  

   1280x1024     60.02  

   1280x720      60.00    59.94    50.00    29.97    23.97  

   1152x864      75.00  

   1024x768      60.00  

   800x600       60.32  

   720x576       50.00  

   720x480       59.94  

   640x480       59.94    59.93  

DP-0 connected 1080x1920+4920+0 left (normal left inverted right x axis y axis) 598mm x 336mm

   1920x1080     60.00*+

   1600x900      60.00  

   1280x1024     75.02    60.02  

   1152x864      75.00  

   1024x768      75.03    60.00  

   800x600       75.00    60.32  

   640x480       75.00    59.94  

DP-1 disconnected (normal left inverted right x axis y axis)

DP-2 disconnected (normal left inverted right x axis y axis)

DP-3 disconnected (normal left inverted right x axis y axis)

DP-4 connected 1080x1920+0+0 left (normal left inverted right x axis y axis) 598mm x 336mm

   1920x1080     60.00*+

   1600x900      60.00  

   1280x1024     75.02    60.02  

   1152x864      75.00  

   1024x768      75.03    60.00  

   800x600       75.00    60.32  

   640x480       75.00    59.94  

DP-5 disconnected (normal left inverted right x axis y axis)

NVIDIA X Server Settings shows both cards, and each monitor is shown as a display device both cards.

GPU 0 - (GeForce GTX 1080)

Shows nominal GPU utilization fluctuating with system use.

Shows all three monitors.

GPU 1 (GeForce GT 710)

Shows no GPU utilization.

Shows all three monitors.

Both cards appear to be working, but I cannot get a display signal out of the second card. Both cards are known-good hardware, and I cannot move forward with the guest pass-through until I get this issue sorted out.

Looking for a way forward.