Not all OCuLink eGPU docks are created equal

Summary

I recently tried using the Minisforum DEG1 GPU Dock with a Raspberry Pi 500+, using an M.2 to OCuLink adapter, and this chenyang SFF-8611 Cable. After figuring out there's a power button on the DEG1 (which needs to be turned on), and after fiddling around with the switches on the PCB (hidden under the large metal plate on the bottom; TGX to OFF was the most important setting), I was able to get the Raspberry Pi's PCIe bus to at least tell the graphics card installed in the eGPU dock to spin up its fans and initialize. But I wasn't able to get any output from the card (using this Linux kernel patch), and lspci did not show it. (Nor were there any logs showing errors in dmesg). I switched back to my JMT eGPU OCuLink dock for the rest of my testing, and uploaded a video detailing some of my struggles, and a blog post detailing the Pi 500+ eGPU testing. A few commenters mentioned they too had issues with the Minisforum DEG1. But a few of them looked closely at the OCuLink cable Minisforum included, and noted there were a couple extra colored wires going through the cable sleeve that didn't seem to be present on other cables—like the chenyang I was using! They suggested I try swapping cables. So I did... and testing it with an RX 6500 XT worked! Looking closely at the cables side by side, I can confirm what some of the commenters said: the cable that came with the DEG1 looks like it has additional colored wires going between the connectors. Moral of the this portion of the story: not all OCuLink cables are created equal. Going Deeper But then I swapped back to my RX 7900 XT, the one that was previously unrecognized in the Miniforum dock... and it still wouldn't work. $ lspci 0002:00:00.0 PCI bridge: Broadcom Inc. and subsidiaries BCM2712 PCIe Bridge (rev 30) 0002:01:00.0 Ethernet controller: Raspberry Pi Ltd RP1 PCIe 2.0 South Bridge I tried all three switches in different settings, I tried swapping OCuLink cables back and forth again... nothing. The RX 6500 XT was happy...