Success! Sort of? External graphics cards work on the Raspberry Pi

[sounds]

Jeff Geerling and a big list of other people have finally gotten an external PCIe GPU to work using the PCIe x1 slot on the Pi Compute Module 4.

 

The internal GPU on the Compute Module 4 is faster than the external card!

 

Quote

In October 2020, after Raspberry Pi introduced the Compute Module 4, I started out on a journey to get an external graphics card working on the Pi.

What works

[VisionTek Radeon 5450 1GB]

 

In summary: DisplayPort, VGA, HDMI, and DVI ports. The command line (console), Xorg, and Weston (a reference implementation of Wayland), as well as some 3D benchmarks and applications that use OpenGL.

 

But Xorg especially shows a lot of 'glitches' in its output (see above), especially when interacting with different screen elements.

Weston (pictured above) didn't have the same glitchy behavior, but ran a bit sluggish and would often lock up after a while (necessitating a soft reboot).

https://youtu.be/crnEygp4C6g

[geerlingguy]

The internal GPU is currently faster due to highly unoptimizable code in our patched driver, plus the x1 Gen 2.0 bandwidth available. I hope we can at least get a feature like H.264 transcoding working because that could actually make these older GPUs useful again