External graphics cards work on the Raspberry Pi

"Work", in this case, meaning you can get a display to run through one. I've tested DVI, VGA, HDMI, and DisplayPort across four different graphics cards (three AMD 5000-7000 series, and one SM750 card from ASRock Rack.

A console (CLI) runs great and is stable, but Xorg and Wayland (well, Weston at least) are a little less stable. And with the MMIO modifications we had to make to work around the Pi SoC's (BCM2711) flaws, things are a bit slow currently.

And other SBC SoCs seem to have similar PCIe hardware-level issues (like the RK3588 in the Pine64 SOQuartz, at least). Tons more detail can be found in these two GitHub threads:

https://github.com/geerlingguy/raspberry-pi-pcie-devices/iss...

https://github.com/geerlingguy/raspberry-pi-pcie-devices/iss...

(Both issues are over GitHub's limit, so you have to show hidden items to see the whole progression.)

This is like building a motorcycle on a 350cid v8 engine. Lovely absurd insanity.