[sane-devel] FreeBSD and Microtek Scanmaker II
Sun, 22 Jun 2003 12:39:13 -0400
>are you sure that the Linux SCSI system (or FreeBSD) tries to issue a
>REQUEST SENSE, if it can't "connect" to device? (If I find enough time,
I'm not exactly sure what is going on in this particular situation.
Last winter, a user (Shawn Rutledge) was really helpful in tracking
down lost sense codes. The backend sense handler was getting called with
all zeros, as here. By slogging through debug output from the driver for
the SCSI card in the kernel logs, it was apparent that the REQUEST SENSE
was indeed issued. I then dug into the mid-level scsi driver and found
at least one place where the results were being thrown away.
The moral to the story is that I don't trust the error codes returned by
the Linux SCSI system --- since it thinks that the results of the REQUEST
SENSE are invalid, it decides that there must be some other problem.
The trigger for this behavior is the peculiar sense codes from Microtek