As best I can tell, this is because the L860 has a USB transmitter but isn’t driving it due to being in PCIe mode. The USB hub thinks a USB device is there and keeps trying to talk to it.
This will require a firmware update to disable the USB port attached to the M.2 slot when it sees this class of device. The Ten64 u-boot already does this when it sees a NVMe SSD in the Key B.
If you get tired of seeing it, here is a kernel patch that silences this particular log message.
I haven’t found a suitable one (at least that is easily obtainable) for indoor use. The “4x4 MIMO” ones out there tend to be for vehicles or for “hotspots on wheels”.
Will be covered in the aforementioned application note. In the meantime:
These are good ‘whip’ antennas that work on both WiFi bands:
For MiniPCIe WiFi cards, you need RP-SMA to UFL bulkhead connectors, my suggestion would be to grab two short (~150mm) ones and two longer ones (~300mm) to be installed either side on the Ten64.
Example of a 150mm: CA-DKCA1-152L1-ALI0
For M.2 Cellular modems, you need SMA to MHF4, like CAB.S02
(Warning: due to how small the MHF4/card connector is, they can only be connected and removed several times before they break. It’s a good to have a couple of spares)
- 8mm spanner to tighten the SMA connectors to the enclosure
- A suitable silicone adhesive to ‘glue’ down the antenna connectors onto the modem and WiFi cards (otherwise they could get dislodged during transport). Dow 744 is what we use. Not required for ‘lab’ use.
Yes, the entire ‘WWAN’ stack is new in 5.14, previously most cards used USB drivers and these cards sat out of the tree.
I’ll add it to the next kernel build for 5.14.