USB: storage devices and SAT

Add the SANE SENSE flag to indicate that a device is capable of handling
more than 18-bytes of sense data.  This functionality is required for
USB-ATA bridges implementing SAT.  A future patch will actually enable this
function for several devices.

The logic behind this is that we can detect support for SANE_SENSE in a few ways:
 1) ATA PASS THROUGH (12) or (16) execute successfully
 2) SPC-3 or higher is in use
 3) A previous CHECK CONDITION occurred with sense format 70-73 and had
    a length greater than 18-bytes total

Signed-off-by: Ben Efros <ben@pc-doctor.com>
Signed-off-by: Matthew Dharm <mdharm-usb@one-eyed-alien.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 4 insertions, 0 deletions

diff --git a/drivers/usb/storage/scsiglue.c b/drivers/usb/storage/scsiglue.c
index 09779f6a8179..1b35e011a34f 100644
--- a/drivers/usb/storage/scsiglue.c
+++ b/drivers/usb/storage/scsiglue.c
@@ -170,6 +170,10 @@ static int slave_configure(struct scsi_device *sdev)
                 if (us->fflags & US_FL_CAPACITY_HEURISTICS)
                         sdev->guess_capacity = 1;
 
+                /* assume SPC3 or latter devices support sense size > 18 */
+                if (sdev->scsi_level > SCSI_SPC_2)
+                        us->fflags |= US_FL_SANE_SENSE;
+
                 /* Some devices report a SCSI revision level above 2 but are
                  * unable to handle the REPORT LUNS command (for which
                  * support is mandatory at level 3).  Since we already have