P33M

I've now got one in my possession. The device can't handle being suspended, and never responds to SETUP packets after a resume. You can reproduce this without a Pi 4...

I can recover the port state by forcibly power cycling the Pi 4's downstream ports with uhubctl. `sudo uhubctl -l 1-1 -a 2` brings it back to life. It's not...

As in, the hub either does not implement any Vbus switching at all (no hardware support) or it doesn't use an upstream port disconnect to imply "turn off downstream Vbus".

I don't think this is fixable. Error states for config reads (completion timeout, or unsupported request) from the PCIe core propagate back as an AXI error response. Bus errors are...

I was a bit suspicious of the timeout interval - 10.8 ish seconds - and the only counters that are large enough are the RGR bridge control registers (aka plumbing...

Unfortunately not. Bandwidth calculations for split transactions (full-speed / low-speed) on the Pi 4 are delegated to the VL805 firmware, and we've already got a version that claims to support...

The available bandwidth should be at least 1012 periodic bytes per frame total, and I would expect altsetting 2 to be no more than 576 bytes per frame, so the...

All of the S24_3LE sample rates are assigned to bAlternateSetting = 2, so this explains why you get bandwidth errors for every choice. This is overkill as it causes an...

> Is there some extra constraint for RPi USB that's not there for your typical Intel USB chipset? Yes, as I said in my first response. The limitation is not...

> The bandwidth calculation is handled by the VL805 firmware. Can you point me to the source file that does the handing-off? xhci_configure_endpoint() in drivers/usb/host/xhci.c submits a TRB to the...