On 06/27/12 18:31, Hans Petter Selasky wrote:
On Wednesday 27 June 2012 17:28:30 Alexander Motin wrote:
On 06/27/12 18:17, Hans Petter Selasky wrote:
On Wednesday 27 June 2012 17:08:29 Alexander Motin wrote:
umass problem


Are you verifying the received data length for the SCSI commands reading
out various data?

Mentioned revision beyond others adds check for the sense data length in
case of error. It won't even look into the sense data if reported amount
(sense_len - sense_resid) is zero or less then needed. I have no idea
how USB calculates resid, but it may be a problem in this case. I think
it could be useful to get USB packets trace to see whether it is device
doesn't return any sense data, or umass improperly interprets them in
this case for some reason.


The residue is part of the 13 status bytes in the SCSI BOT protocol. If this
field is zero, the umass driver will compute the residue from the actual data
transferred as a workaround.

Can't there be an opposite bug -- residue field is equal to the transfer size in which case CAM will think there is no sense data?

Alexander Motin
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