Hi, Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> writes: > On Mon, 16 Jan 2017, Felipe Balbi wrote: > >> Sorry for the long delay, I finally have more information on this. All >> this time I was doing something that I never considered to matter: I've >> been running host and peripheral on the same machine. Now that I have >> tracepoints on xHCI as well, I could see that these 30 seconds of >> "nothing" is actuall full of xHCI activity and I can see that for the >> duration of these 30 seconds preempt depth on the CPU that (eventually) >> queues a request on dwc3, is always > 1 (sometimes 2, most of the time >> 1). My conclusion from that is that xHCI (or usbcore ?!?) locks the CPU >> and g_mass_storage is spinning for over 30 seconds at which point >> storage.ko (host side class driver) dequeues the request. >> >> I'll see if I can capture a fresh trace with both xHCI and dwc3 with >> this happening, but probably not today (testing stuff for -rc). > > Does anything change if the host and peripheral are separate machines? couldn't reproduce the problem yet ;-) -- balbi -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
