usb-storage: fix for UFI LUN detection
The UFI specification doesn't permit devices to indicate non-existent
LUNs in the manner prescribed by the SCSI spec. This patch (as773)
sets a special flag so that the SCSI scanner will recognize these
devices and treat them specially.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Matthew Dharm <mdharm-usb@one-eyed-alien.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/usb/storage/scsiglue.c b/drivers/usb/storage/scsiglue.c
index a4b7df9..e1072d5 100644
--- a/drivers/usb/storage/scsiglue.c
+++ b/drivers/usb/storage/scsiglue.c
@@ -72,12 +72,27 @@
static int slave_alloc (struct scsi_device *sdev)
{
+ struct us_data *us = host_to_us(sdev->host);
+
/*
* Set the INQUIRY transfer length to 36. We don't use any of
* the extra data and many devices choke if asked for more or
* less than 36 bytes.
*/
sdev->inquiry_len = 36;
+
+ /*
+ * The UFI spec treates the Peripheral Qualifier bits in an
+ * INQUIRY result as reserved and requires devices to set them
+ * to 0. However the SCSI spec requires these bits to be set
+ * to 3 to indicate when a LUN is not present.
+ *
+ * Let the scanning code know if this target merely sets
+ * Peripheral Device Type to 0x1f to indicate no LUN.
+ */
+ if (us->subclass == US_SC_UFI)
+ sdev->sdev_target->pdt_1f_for_no_lun = 1;
+
return 0;
}