I have a compute rig with an ASpeed AST2400 GPU I use for the display and 3x GTX 980s for computing. I would like to overclock the nvidia gpus, which requires setting the coolbits option in xorg.conf.
So far I have been able to switch from modesetting to using xorg.conf using the following configuration (by setting dummy monitors for the GPUs):
# nvidia-xconfig: X configuration file generated by nvidia-xconfig
# nvidia-xconfig: version 381.22 (buildmeister@swio-display-x86-rhel47-02) Thu May 4 01:29:00 PDT 2017
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"
FontPath "/usr/share/fonts/default/Type1"
EndSection
Section "InputDevice"
# generated from default
Identifier "Mouse0"
Driver "mouse"
Option "Protocol" "auto"
Option "Device" "/dev/input/mice"
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"
HorizSync 28.0 - 33.0
VertRefresh 43.0 - 72.0
Option "DPMS"
EndSection
Section "Monitor"
Identifier "Monitor2"
VendorName "Unknown"
ModelName "Unknown"
HorizSync 28.0 - 33.0
VertRefresh 43.0 - 72.0
Option "DPMS"
EndSection
Section "Monitor"
Identifier "Monitor3"
VendorName "Unknown"
ModelName "Unknown"
HorizSync 28.0 - 33.0
VertRefresh 43.0 - 72.0
Option "DPMS"
EndSection
Section "Device"
Identifier "Device0"
Driver "modesetting"
VendorName "ASpeed"
BoardName "AST2400"
BusID "PCI:7:0:0"
EndSection
Section "Device"
Identifier "Device1"
Driver "nvidia"
VendorName "NVIDIA Corporation"
BoardName "GeForce GTX 980"
BusID "PCI:2:0:0"
EndSection
Section "Device"
Identifier "Device2"
Driver "nvidia"
VendorName "NVIDIA Corporation"
BoardName "GeForce GTX 980"
BusID "PCI:81:0:0"
EndSection
Section "Device"
Identifier "Device3"
Driver "nvidia"
VendorName "NVIDIA Corporation"
BoardName "GeForce GTX 980"
BusID "PCI:82:0:0"
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
Option "Coolbits" "8"
SubSection "Display"
Depth 24
EndSubSection
EndSection
Section "Screen"
Identifier "Screen2"
Device "Device2"
Monitor "Monitor2"
DefaultDepth 24
Option "Coolbits" "8"
SubSection "Display"
Depth 24
EndSubSection
EndSection
Section "Screen"
Identifier "Screen3"
Device "Device3"
Monitor "Monitor3"
DefaultDepth 24
Option "Coolbits" "8"
SubSection "Display"
Depth 24
EndSubSection
EndSection
However I cannot enter nvidia-settings because it complains that I am not using the nvidia xorg driver. Everything else is configured properly (my CUDA programs work fine and nvidia-smi reports no problems).
So is it possible to overclock compute cards if I’m using the modesetting driver for my real display?