On Tue, Dec 17, 2019 at 11:33:55AM -0500, Bryan Gillespie wrote: > Hello, > > I am trying to debug a USB 3.0 issue under linux 4.4/4.14 where device > endpoints become unresponsive when sending small packet iperf traffic > through them. I have a protocol analyzer (Beagle 5000), and I see the > following at the moment of breakage: Does 5.4 also show this issue? > https://i.stack.imgur.com/CrCV7.png > > If I expand the packets, I notice that the last good transaction looks > like this: > > https://i.stack.imgur.com/sWxne.png > > And the first bad transaction looks like this: > > https://i.stack.imgur.com/l85xJ.png > > This looks like only a partial transaction? The only thing that stuck > out to me was that the two data transactions have the exact same > Sequence Number (SeqNum), which seems like it might be out of spec > with USB 3.0 (I read that you can only have duplicate sequence numbers > if it is a retransmission, and it looks like it isn't)? Is xhci under > linux setting these sequence numbers or is that at the hardware level? > This issue seems to bubble up the linux usb stack as -EPROTO which has > no information. The hardware handles the sequence number, so you might want to make sure you are using up-to-date silicon. thanks, greg k-h
