PSA: GTi13 Ultra + EX Pro + Arc Pro B70 on Linux - lspci reports Gen1 x1 but the link is actually fine

Almost RMA'd my dock tonight over nothing, posting in case it saves someone else the same five hours.

Got my Arc Pro B70 today, plugged it into the EX Pro on my GTi13 Ultra, did the whole Linux dance (kernel update for BMG-G31 device IDs, removed a sneaky pci=nomsi from grub that was blocking the xe driver, etc) and finally got the card recognized. Then I check lspci and it's reporting the link as PCIe Gen1 x1. Gen 1. One lane. Worst possible.

So obviously I assumed the dock was cooked. Cold-cycled it, drained the caps, reseated the card, played with every BIOS PCIe option I could find, even drafted an RMA email to Beelink support. Nothing changed it.

Then I opened nvtop literally just to admire the 32GB of VRAM, and it said PCIe GEN 3@ 8x right there at the top. Wait what.

Ran an actual host-to-device bandwidth test in PyTorch - 5.07 GB/s. That's Gen3 x8. Proper 7.something GB/s on another benchmark. The link was fine the entire time. The dock isn't broken at all. The PCIe switch's LnkCap registers in config space are just lying, and lspci and sysfs both faithfully report the lie.

So if you see Gen1 x1 in lspci on this combo, don't trust it, measure actual bandwidth before doing anything drastic. nvtop or a real workload (preferably over nvtop ofc) will tell you the truth.

Full writeup with all the other gotchas (kernel version, the grub flag, missing compute runtime on Debian, NIC quirks, the works) here:

👉 https://github.com/Vem0n/beelink-arcb70

Setup: GTi13 Ultra (BIOS GTiT104), EX Pro Dock, Arc Pro B70 32GB, Debian 13 Trixie with kernel 6.19.13 from backports.