Commit f3f49065 authored by Alan Stern's avatar Alan Stern Committed by Greg Kroah-Hartman
Browse files

usb-storage: SCSI level fixes 



This patch (as835) removes from usb-storage the code which sets all
devices to a SCSI level of at least SCSI-2.  The original reasons for
doing this no longer apply, and in fact it prevents certain kinds of
ATA pass-thru commands from being used.

The patch also marks CB and CBI devices that are SCSI-0 (legacy SCSI)
as being single-LUN, since the combined SCSI-over-USB transport
protocol has no way to convey LUN information to these devices.

Signed-off-by: default avatarAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: default avatarMatthew Dharm <mdharm-usb@one-eyed-alien.net>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent 85a975d0

drivers/usb/storage/scsiglue.c

+13 −18
Original line number Diff line number Diff line
@@ -110,23 +110,6 @@ static int slave_configure(struct scsi_device *sdev) 
	 * the end, scatter-gather buffers follow page boundaries. */

	blk_queue_dma_alignment(sdev->request_queue, (512 - 1));



	/* Set the SCSI level to at least 2.  We'll leave it at 3 if that's

	 * what is originally reported.  We need this to avoid confusing

	 * the SCSI layer with devices that report 0 or 1, but need 10-byte

	 * commands (ala ATAPI devices behind certain bridges, or devices

	 * which simply have broken INQUIRY data).

	 *

	 * NOTE: This means /dev/sg programs (ala cdrecord) will get the

	 * actual information.  This seems to be the preference for

	 * programs like that.

	 *

	 * NOTE: This also means that /proc/scsi/scsi and sysfs may report

	 * the actual value or the modified one, depending on where the

	 * data comes from.

	 */

	if (sdev->scsi_level < SCSI_2)

		sdev->scsi_level = sdev->sdev_target->scsi_level = SCSI_2;



	/* Many devices have trouble transfering more than 32KB at a time,

	 * while others have trouble with more than 64K. At this time we

	 * are limiting both to 32K (64 sectores).
@@ -176,7 +159,9 @@ static int slave_configure(struct scsi_device *sdev) 
		 * a Get-Max-LUN request, we won't lose much by setting the

		 * revision level down to 2.  The only devices that would be

		 * affected are those with sparse LUNs. */

		sdev->scsi_level = sdev->sdev_target->scsi_level = SCSI_2;

		if (sdev->scsi_level > SCSI_2)

			sdev->sdev_target->scsi_level =

					sdev->scsi_level = SCSI_2;



		/* USB-IDE bridges tend to report SK = 0x04 (Non-recoverable

		 * Hardware Error) when any low-level error occurs,
@@ -194,6 +179,16 @@ static int slave_configure(struct scsi_device *sdev) 
		sdev->use_10_for_ms = 1;

	}



	/* The CB and CBI transports have no way to pass LUN values

	 * other than the bits in the second byte of a CDB.  But those

	 * bits don't get set to the LUN value if the device reports

	 * scsi_level == 0 (UNKNOWN).  Hence such devices must necessarily

	 * be single-LUN.

	 */

	if ((us->protocol == US_PR_CB || us->protocol == US_PR_CBI) &&

			sdev->scsi_level == SCSI_UNKNOWN)

		us->max_lun = 0;



	/* Some devices choke when they receive a PREVENT-ALLOW MEDIUM

	 * REMOVAL command, so suppress those commands. */

	if (us->flags & US_FL_NOT_LOCKABLE)

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