Comment 11 for bug 2026790

worse still , now I cannot get a gdm login unless I disconnect the USB-C eGPU (this NVIDIA GPU enclosure).

I am reading up further on "prime" and "reverse prime" GPUs. The behavior here may be similar:
https://forums.developer.nvidia.com/t/failed-to-lookup-gem-object-for-mapping/186526

Here is a log of the connect/disconnect (see attached log).