On 12/06/2011 01:19 AM, Sancho Dauskardt wrote: > On 05.12.2011 17:38, Alan Stern wrote: >> On Mon, 5 Dec 2011, Sancho Dauskardt wrote: >> [...] >> Can you get in touch with the technical support people at the company >> that sells the disk drive's USB interface? (You may have to tell them >> about the problem you see under Windows; many companies claim not to >> support Linux.) >> > So far we are only talking to the hub guys, as the chain AMD SB7xx + > SMSC251x + bad storage device is needed to trigger the fault - plus the > NAK'ing usblp. > AMD - anybody here ? > There is a known issue on SB700 with usb hub, see commit b09bc6cb "USB: fix SB700 usb subsystem hang bug". Other than that, I'm not aware of any SB700 EHCI issues involved with USB hub. Thanks, Andiry >>> makrSo what we have: >>> - when 'under NAK load' SB710 EHCI misses an incomming data packet and >>> thus doesn't send an ACK. >>> - AU63xx doesn't handle the missing ACK properly. >>> - we also have some usb-sticks that don't react mit missing ACK's >>> properly. >>> >>> Could this be related to the current Webcam issue ? >>> >> I don't think so. That problem clearly lies in the host controller, >> not the device. The controller takes an excessively long time (up to >> 8 ms instead of no more than 1 ms) to shut down the periodic schedule. >> >> > True, but to me it seems like the HC is busy with the last NAK and thus > missing the incomming data for the next one. > > >>>>> Normally an ACK would come 9100ns after the data packet (Data: 21.429 >>>>> 518 444 vs. ACK: 21.429 527 517). >>>>> >>>>> >>>> That seems awfully long. According to the USB-2 spec (section >>>> 7.1.18.2), high-speed inter-packet delays are supposed to be no more >>>> than 192 bit times. That's less than half a microsecond. >>>> >> Did you ever figure this out? >> >> > The timing includes the actual transfer of the data packet - which then > makes sense, right ? > > - sda > > > > > -- > 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 > -- 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
