Thank you for the ideas.
Currently, I have no xorg.conf file set up at all, since I read that the xorg.conf file is apparently complicating the usage of the NVIDIA GPU leading to errors and problems.
However, I also tried to solve this problem by using different xorg.conf files. So I did not edit it per hand or anything, but I tried out two different xorg.conf files:
One of them was created by using “nvidia-xconfig” and the other one was created by using “nvidia-xconfig --enable-all-gpus”. I had this idea from the following forum post: Ubuntu 18.04 Uses LLVM instead of NVIDIA Drivers for OpenGL - #2 by aplattner
The first xorg.conf file created with “nvidia-xconfig” generates the following file:
nvidia-xconfig: X configuration file generated by nvidia-xconfig
nvidia-xconfig: version 460.73.01
Section “ServerLayout”
Identifier “Layout0”
Screen 0 “Screen0”
InputDevice “Keyboard0” “CoreKeyboard”
InputDevice “Mouse0” “CorePointer”
EndSection
Section “Files”
EndSection
Section “InputDevice”
# generated from default
Identifier “Mouse0”
Driver “mouse”
Option “Protocol” “auto”
Option “Device” “/dev/psaux”
Option “Emulate3Buttons” “no”
Option “ZAxisMapping” “4 5”
EndSection
Section “InputDevice”
# generated from default
Identifier “Keyboard0”
Driver “kbd”
EndSection
Section “Monitor”
Identifier “Monitor0”
VendorName “Unknown”
ModelName “Unknown”
Option “DPMS”
EndSection
Section “Device”
Identifier “Device0”
Driver “nvidia”
VendorName “NVIDIA Corporation”
EndSection
Section “Screen”
Identifier “Screen0”
Device “Device0”
Monitor “Monitor0”
DefaultDepth 24
SubSection “Display”
Depth 24
EndSubSection
EndSection
And the second xorg.conf file created with “nvidia-xconfig --enable-all-gpus” generates the following file:
nvidia-xconfig: X configuration file generated by nvidia-xconfig
nvidia-xconfig: version 460.73.01
Section “ServerLayout”
Identifier “Layout0”
Screen 0 “Screen0”
Screen 1 “Screen1” RightOf “Screen0”
Screen 2 “Screen2” RightOf “Screen1”
Screen 3 “Screen3” RightOf “Screen2”
InputDevice “Keyboard0” “CoreKeyboard”
InputDevice “Mouse0” “CorePointer”
EndSection
Section “Files”
EndSection
Section “InputDevice”
# generated from default
Identifier "Mouse0"
Driver "mouse"
Option "Protocol" "auto"
Option "Device" "/dev/psaux"
Option "Emulate3Buttons" "no"
Option "ZAxisMapping" "4 5"
EndSection
Section “InputDevice”
# generated from default
Identifier "Keyboard0"
Driver "kbd"
EndSection
Section “Monitor”
Identifier “Monitor0”
VendorName “Unknown”
ModelName “Unknown”
Option “DPMS”
EndSection
Section “Monitor”
Identifier “Monitor1”
VendorName “Unknown”
ModelName “Unknown”
Option “DPMS”
EndSection
Section “Monitor”
Identifier “Monitor2”
VendorName “Unknown”
ModelName “Unknown”
Option “DPMS”
EndSection
Section “Monitor”
Identifier “Monitor3”
VendorName “Unknown”
ModelName “Unknown”
Option “DPMS”
EndSection
Section “Device”
Identifier “Device0”
Driver “nvidia”
VendorName “NVIDIA Corporation”
BoardName “Tesla V100-SXM2-16GB”
BusID “PCI:97:0:0”
EndSection
Section “Device”
Identifier “Device1”
Driver “nvidia”
VendorName “NVIDIA Corporation”
BoardName “Tesla V100-SXM2-16GB”
BusID “PCI:98:0:0”
EndSection
Section “Device”
Identifier “Device2”
Driver “nvidia”
VendorName “NVIDIA Corporation”
BoardName “Tesla V100-SXM2-16GB”
BusID “PCI:137:0:0”
EndSection
Section “Device”
Identifier “Device3”
Driver “nvidia”
VendorName “NVIDIA Corporation”
BoardName “Tesla V100-SXM2-16GB”
BusID “PCI:138:0:0”
EndSection
Section “Screen”
Identifier “Screen0”
Device “Device0”
Monitor “Monitor0”
DefaultDepth 24
SubSection “Display”
Depth 24
EndSubSection
EndSection
Section “Screen”
Identifier “Screen1”
Device “Device1”
Monitor “Monitor1”
DefaultDepth 24
SubSection “Display”
Depth 24
EndSubSection
EndSection
Section “Screen”
Identifier “Screen2”
Device “Device2”
Monitor “Monitor2”
DefaultDepth 24
SubSection “Display”
Depth 24
EndSubSection
EndSection
Section “Screen”
Identifier “Screen3”
Device “Device3”
Monitor “Monitor3”
DefaultDepth 24
SubSection “Display”
Depth 24
EndSubSection
EndSection
So the normal nvidia-xconfig does not give out device sections including the BusID, but the “enable all gpus” setting does that actually.
However, it also did not work with either of these two xorg.conf files.
Apart from that I did not try or even know how to force an EDID for each card in the xorg.conf file or start X as one of the cards main display and use the working adapter/display. I will look into that and can give feedback regarding that later on.
But the ideas are all very good and worth pursuing, thank you very much for your input.