abel deuring wrote: > > Dave Close wrote: > > > > I am dealing with a scanner that seems to return some of its status > > outside the SCSI sense byte area. sanei_scsi reports this information > > via DBG but doesn't provide it to the sense handler. The data is in the > > SCSI header, which is physically adjacent to and preceding the sense > > bytes in sanei_scsi.c, so I can get to it with some C tricks. But, of > > course, those tricks could fail in a future SANE version. Is there a > > better recommended solution? > > > > Here's the kind of debug output I'm seeing. > > > > [sanei_scsi] sanei_scsi_req_wait: read 64 bytes > > [sanei_scsi] sanei_scsi_req_wait: SCSI command complained: Success > > [sanei_scsi] sense buffer: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 > > [sanei_scsi] target status: 02 host status: 0000 driver status: 0018 > > [mybackend] sense=00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 > > > > The fourth line above shows target status and driver status. This > > information does not appear to be available to the sense handler. If > > sanei_scsi knows enough to call the sense handler in this case, and it > > does, it should provide all the relevant data. > > Dave, > > It does not make much sense to forward the words host status and driver > status to the backend, because they are Linux-specific, while the > backends should be able to work with a number of different OSes, which > might provide completely different status information. > > I've inserted the DBG statements, because it makes bug tracing more > convenient: If host status or driver status are non-zero, one should > check for possible inconsistencies in the SCSI command sent (e.g., wrong > CDB length, wrong data length), for possible bugs in sanei_scsi.c or in > the backend; if things look fine, it's time to ask the kernel developers > for help.
Sorry, I am obviously too tired to read and write mails ;) So, an addition: That the sense handler cannot "see" the target status byte, in indeed a flaw of sanei_scsi.c. I have some ideas to improve the sanei_scsi interface for Sane 2, and forwarding the SCSI status byte to the backend is indeed part of the ideas, but I am currently too busy with other stuff to write down what I have in my mind. Abel
