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usb-storage: fix for UFI LUN detection

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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>
This commit is contained in:
Alan Stern 2006-08-21 12:00:53 -04:00 committed by Greg Kroah-Hartman
parent e113f29c90
commit 3a3416b12f
1 changed files with 15 additions and 0 deletions
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15
drivers/usb/storage/scsiglue.c
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@ -72,12 +72,27 @@ static const char* host_info(struct Scsi_Host *host)
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;
}