Hi, On Tue, May 8, 2012 at 12:25 PM, Sarah Sharp <sarah.a.sharp@xxxxxxxxxxxxxxx> wrote: > On Tue, May 08, 2012 at 10:56:59AM -0400, Alan Stern wrote: >> On Tue, 8 May 2012, Sergio Correia wrote: >> >> > the output from USBmon for both EHCI and xHCI is available at: >> > http://www.uece.net/misc/usb-headset-problem/usbmon-usb2-bus2-dev6.txt >> > http://www.uece.net/misc/usb-headset-problem/usbmon-usb3-bus3-dev5.txt >> >> It's notable that the bus-2 trace (which I presume is the one using >> EHCI) shows that even though each packet requested 96 bytes of data, >> the device sent only 88 or 90 bytes. By contrast, the bus-3 trace >> (xHCI) shows that each packet contained 96 bytes. We should expect the >> two traces not to differ in this way. >> >> This may be a bug in the xhci-hcd driver -- it may say it got more >> bytes than actually were received. > > I actually suspect it might be a bug in the hardware itself. The lspci > shows it's a very early Fresco Logic chipset revision, and it wouldn't > surprise me if the xHCI host just doesn't report the short packet > completion code. Let's rule that out before I go digging around the > xHCI ring code (which looks like it's handling short packets properly, > BTW). > > Sergio, can you apply the attached patch, and see if the host is > actually reporting short packets? the dmesg is there: http://www.uece.net/misc/usb-headset-problem/dmesg-short-packet-completion-code.bz2 it was too large, so I bzip'ed it. sergio > > Sarah Sharp -- 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
