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. 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). Thanks for all the help, Marcel -- 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
