On Wed, 20 Apr 2011, Marcel wrote: > On Sunday, April 17, 2011 01:46:26 am Alan Stern wrote: > > On Sat, 16 Apr 2011, Marcel wrote: > > > Hi, > > > > > > > > Most likely the root cause is a hardware bug in the Atmel G45. > > > > > However the only way to prove this would be to replace the G45 with a > > > > > different kind of system. > > Just to post a reply I got from Atmel. It seem my issue is related to a known > issue (which btw was not public yet). > > Errata: > UHPHS: Packet Loss Issue in the UTMI Transceivers > > High-Speed USB Host may lose incoming packets when connected to an external > USB Hub. > > A high data transfer error rate has been observed on the High-Speed USB Host > interface when connected to an external USB Hub. The USB remains functional > but the errors may require a reset of the USB interface to recover. > > The Full-Speed USB Host operation is not affected by this problem. > > Problem Fix/Workaround > > A workaround consists of implementing a timeout on the USB communication using > one of the timers in the device and trigger a reset of the USB Host interface > via software and restart the communication. The impact of the workaround on > the data rate is depending on the error rate observed in the application but > can be such that streaming data at high rates becomes impractical. Too bad. This may not be exactly the error that you see, but it seems pretty close. > They mention packet loss. This may be true as the error I got (bad packet > length) always occurred at a moment where I should have received incoming > data. I than received a packet, no further packets. > > In short, I have no other workaround than to use full speed hubs. > I think for now we can close this subject and I think Alan's first impression > as mentioned above was after all true (unfortunately). Can you use non-Atmel hardware instead? Alan Stern -- 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
