I'm running Ubuntu 24.04 on my tachyon and have the following hats installed:
Waveshare 2-channel PCIe bridge
MCUZONE 2 port 2.5 Gb ethernet hat
Radaxa Penta Sata hat powering the whole stack with a robust ATX power supply
Throughout the testing the Radaxa works all the time. The MCUZONE dual ethernet hat works when directly connected to the tachyon PCIe interface. When the MCUZONE is linked through the waveshare, it never grabs and IP and multiple errors in dmesg. I've been using Gemini to help me troubleshoot and the consensus is that the waveshare is introducing either noise or the tachyon is sending commands to it at a different clock speed that it cannot keep up with. Is anyone else using a PCIe bridge successfully with a R8125 based hat like I have? I thought it was simply that the kernel didn't support the card, but clearly it works when directly connected to the Tachyon.
EDIT: I just realized that the waveshare hat says "gen2" on it and I think the Tachyon is gen 3 so the MCUZONE is expecting gen3 bus speed and not getting it. Lesson learned.