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I have to little knowledge of USB and OHCI to judge this errata with it suggested workaround myself. Will this work or should we design in an external USB host? "14 Bit stuffing right before the EOP (USB) Problem; When there is a bit stuffing at the end of the CRC, just before the EOP, (ie CRC = XXXX XXXX 1111 11XX), one byte is added to those already received, giving the first CRC byte received as the last data byte of the received data packet. This delays the EOP recognition by one cycle and generates an extra byte write pulse. As a consequence, the first CRC byte is perceived as a data byte. Implication; Data coming from the USB device may be corrupted Workaround; If the size of the data transfers are known, set the buffer length to the exact number of bytes to be received." Can this workaround be functional? It requires that * Message length is known in advance - are they? When doesn't this hold? Can the OHCI driver be modified or is it written in this way already? * Messages with unknown length does not contain several ones at the end - can this be trusted on? * Retransmit of those messages does not contain the same data at the end - I would be supriced if this is the case. Is another workarounds possible? * Ignore the problem Will this extra data byte cause any problem? Checksum error? Data size errors? Probably not possible - then there would not be this errata in the first place. * If recived message is one to big, check if the last expected byte contains low ones. And if this is the case shorten the message by one. Will this approach result in a check sum errors? Then what about the next approach? * If received messages results in checksum errors, try to receive a one byte shorter message. How is retransmit after checksum error handled? /RogerL ------------------------------------------------------- This SF.net email is sponsored by: SF.net Giveback Program. Does SourceForge.net help you be more productive? Does it help you create better code? SHARE THE LOVE, and help us help YOU! Click Here: http://sourceforge.net/donate/ _______________________________________________ [EMAIL PROTECTED] To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
