On Apr 8, 2019, at 9:33 AM, Alan Stern <stern@xxxxxxxxxxxxxxxxxxx<mailto:stern@xxxxxxxxxxxxxxxxxxx>> wrote: So no disagreement; in both cases the maxpacket values are 1024. Clearly this will not work if a Scatter-Gather component has length 3584. In fact, this bug has nothing at all to do with VHCI. You would observe the same problem if you performed all the accesses on the host computer. In theory, the device should report a block size of 1024. Does it actually do this? A usbmon trace (on the host) showing what happens when the device is first plugged in will provide the answer. Can you collect one and post it? I’ve _never_ seen this on the physical host. My assumption was because the xhci controller supports scatter gather. I will spend some more time trying to reproduce on the physical machine. I will gather this trace, but it might take a bit as I’m locked in meetings. Seth
