[Libcdio-devel] MMC Request Sense changes

[Rocky Bernstein]

The following changes were recently made, and I'm posting them in case folks
have thoughts or concerns.

It was observed that on Microsoft Windows sense data may be returned
although the status given on the command that issues this DeviceIoControl
may report a "normal" status which I guess means here just that the SCSI
pass through command succeeded, not that the operation that was requested
succeeded. This seems to be different than FreeBSD and GNU/Linux which seems
to factor into the return status whether the operation performed succeeded
or not.

In response to the question of whether request sense information can be
returned when there is no error, Thomas reports that there are some
situations where warning information may be returned. For example, if  error
correction was successful on return.

As a result of this, I've added a new enumeration to the
driver_return_code_t -  DRIVER_OP_MMC_SENSE_DATA. This is set when there is
sense data and there isn't a more appropriate status code that was set. For
example on Microsoft Windows, a sense reply for a bad parameter is turned
into a DRIVER_OP_BAD_PARAMETER rather than leaving this as just
DRIVER_OP_MMC_SENSE_DATA. On GNU/Linux some of the specific errno conditions
also get turned into driver_return_code_t enumerations.

Another recent addition is the declaration of the sense reply structure in
mmc.h  This allows one to refer to say the sense_key as a field value rather
than a bit-masked offset into an array of sense bytes.