GPU Passthrough -> lightdm.service won't start

[jamesuk]

@light

vim /etc/X11/xorg.conf.d/20-intel.conf

Section "Device"
  Identifier    "Intel Graphics"
  Driver        "Intel"
  Option "DRI" "3"
EndSection

Would this be the same for a dual AMD gpu setup?
Of course with the identifier and driver changed to AMD I guess.

[light]

I don’t have an AMD GPU to test right now, but I’d assume it would work like this:

/etc/X11/xorg.conf.d/20-amdgpu.conf

Section "Device"
  Identifier "AMDGPU1"
  Driver "amdgpu"
  BusID "PCI:1:0:0"  # Replace this with the actual BusID of your GPU for Qubes
EndSection

The driver may be something else on Qubes, in which case you can check by using lspci -vnn and looking for your VGA compatible controller AMD device. The driver name will be in the “Kernel modules” or “Kernel driver in use” sections.
For the BusID, you’re going to need to find which of the AMD GPUs you want to keep on Qubes, which will be the number before the “VGA compatible controller” on that device.

[deeplow]

@light

I was able to pass through my GPU without even hiding it using boot parameters by just configuring the correct GPU to boot Xorg on.

Nice! However in this case can you still pass it through to a VM? Id’s suspect no since it’s in use by dom0 bur I may be wrong.

[jamesuk]

I somehow managed to boot with rd.qubes.hide_pci but the problem now is that when I start the gpu_HVM I get: “Guest has not initialized the display (yet)”. I’ve looked into this and someone was claiming that I should get an older firmware .bin file from 4.1 and replace it in 4.2 but the problem is that these files are the exact same and behavior doesn’t change.

[deeplow]

@jamesuk

I somehow managed to boot with rd.qubes.hide_pci but

Happy to hear. You don’t happen to know what made it work, correct?

[light]

@deeplow

in this case can you still pass it through to a VM?

Yes I can, and I go from seeing the qubes startup log on the monitor to seeing my HVM whenever I boot it. I’m surprised it works but it does haha. Might just be a case of me being lucky and my GPU model just working for some reason.