Date: Wed, 27 Jun 2012 18:33:45 +0300 From: Alexander Motin <mav@FreeBSD.org> To: Hans Petter Selasky <hselasky@c2i.net> Cc: freebsd-usb@freebsd.org Subject: Re: [usb] Kingston 8Gb is not usable Message-ID: <4FEB27D9.9030408@FreeBSD.org> In-Reply-To: <201206271731.08298.hselasky@c2i.net> References: <4FE9AB28.3070704@passap.ru> <201206271717.02962.hselasky@c2i.net> <4FEB269E.6000508@FreeBSD.org> <201206271731.08298.hselasky@c2i.net>
next in thread | previous in thread | raw e-mail | index | archive | help
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 >>> >>> Hi, >>> >>> 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. > > Hi, > > 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
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?4FEB27D9.9030408>