Re: xhci_hcd / ASMedia ASM4242: Bulk-OUT -EPROTO with Logitec 0789:0308 during DVD+RW recording

[Michal Pecio <michal.pecio@gmail.com>]

On Thu, 10 Sep 2026 20:04:53 +0900, wakasio wrote:
> I looked for the offending TRB in the dump, attached is the full log
> (dyndbg_capture4_trb_dump.log, 1061 lines).

The attachment seems to be missing.
 
> The 11 xhci_dbg lines all say "Transfer error for slot 1 ep 3", same
> address ffffd140425178e0, resid 23552, each followed by "Soft-reset ep
> 3". After the 11th one the driver printed "event ring:" and dumped it,
> then "endpoint ring:" and dumped that too.
> 
> I searched the endpoint ring dump for the DMA address that the event
> ring entries point to. I could not find it. The endpoint ring dump
> covers two segments, 0xfffc00000 to 0xfffc00ff0 and 0xfffbf0000 to
> 0xfffbf0ff0, linked back to each other with a Link TRB. The address in
> question, 0xfffbf8e0, falls between these two ranges, not inside
> either one.

Not sure what happened, I'd like to see the full dump. It's possible
that my patch is wrong and logged some addresses incorrectly, but
I think it should have logged the correct ring and the events must
have matched the ring, or otherwise other errors would be logged.

> I also noticed the event ring entries pointing to that address are all
> labeled "ep 4", not "ep 3".

Yes, 4 is the number used by xHCI, 3 is a driver-internal equivalent.

Regards,
Michal