Cannot enable Coolbits with PRIME render offload

Hi, I’m trying to get the “Coolbits” option to register with PRIME render offload using the 435.17 driver on Arch Linux (HD 530 + GTX 960M). I’ve tried adding it to the Device section:

Section "Device"
        Identifier "nvidia"
        Driver "nvidia"
        Option "Coolbits" "8"
EndSection

to a Screen section:

Section "Screen"
        Identifier "nvidia-screen"
        Device "nvidia"
        Option "Coolbits" "8"
EndSection

and in the OutputClass section:

Section "OutputClass"
        Identifier "nvidia"
        MatchDriver "nvidia-drm"
        Driver "nvidia"
        ModulePath "/usr/lib/nvidia/xorg"
        ModulePath "/usr/lib/xorg/modules"
        Option "Coolbits" "8"
EndSection

but none of them get registered:

cat /var/log/Xorg.0.log | grep -i coolbits
[     9.366] (WW) NVIDIA(G0): Option "Coolbits" is not used

The only way I got it to register was by having a Screen section only for NVIDIA, which resulted in:

[     8.857] (**) NVIDIA(G0): Option "Coolbits" "8"

but without display output (black screen). If I configure Device, Screen or OutputClass sections, I need to have them defined for both GPUs, otherwise it ends up in a black screen (even though Xorg initialization seems to complete).

Adding the option to any integrated GPU sections results in:

[     9.548] (WW) modeset(0): Option "Coolbits" is not used

and it getting ignored.

nvidia-xconfig suggests that Coolbits should be set in the Screen section, but I can’t seem to figure out a working Screen section with PRIME render offload?

Here’s the full xorg.conf:

Section "ServerLayout"
        Identifier "layout"
        Option "AllowNVIDIAGPUScreens"
EndSection

Section "Device"
        Identifier "intel"
        Driver "modesetting"
EndSection

Section "Device"
        Identifier "nvidia"
        Driver "nvidia"
EndSection

Section "OutputClass"
        Identifier "intel"
        MatchDriver "i915"
        Driver "modesetting"
EndSection

Section "OutputClass"
        Identifier "nvidia"
        MatchDriver "nvidia-drm"
        Driver "nvidia"
        ModulePath "/usr/lib/nvidia/xorg"
        ModulePath "/usr/lib/xorg/modules"
EndSection

Section "Screen"
        Identifier "screen1"
        Device "intel"
        Option "Coolbits" "8"
EndSection

Section "Screen"
        Identifier "screen2"
        Device "nvidia"
        Option "Coolbits" "8"
EndSection

Here’s the nvidia-bug-report.log: https://gist.github.com/twelho/5a2b9a35a384ac0174312cfaf90a5f9b. Thanks for your help and time.

I don’t think that will work, for Coolbits to take effect, the nvidia gpu has to drive an X screen which it doesn’t in the offload case.