Some protocols (like USB UFI) or devices that don't adhere to the SCSI
standard may indicate a nonexistent LUN by returning INQUIRY information
with Peripheral Device Type set to 0x1f (unknown or none) and Peripheral
Qualifier set to 0 instead of 3 as the spec requires. This patch (as650)
causes PDT = 0x1f to be recognized as no LUN present regardless of the
qualifier value, if the SCSI level is equal to 0.
Signed-off-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
---
James:
Since nobody objected when I proposed this last week, I'm now submitting
it as a real patch.
Alan Stern
Index: usb-2.6/drivers/scsi/scsi_scan.c
===================================================================
--- usb-2.6.orig/drivers/scsi/scsi_scan.c
+++ usb-2.6/drivers/scsi/scsi_scan.c
@@ -873,6 +873,19 @@ static int scsi_probe_and_add_lun(struct
goto out_free_result;
}
+ /*
+ * Non-standard SCSI devices may set the PDT to 0x1f (unknown or
+ * no device type) instead of using the peripheral qualifier to
+ * indicate that no LUN is present. For example, USB UFI does this.
+ */
+ if (sdev->scsi_level == 0 && (result[0] & 0x1f) == 0x1f) {
+ SCSI_LOG_SCAN_BUS(3, printk(KERN_INFO
+ "scsi scan: peripheral device type"
+ " of 31, no device added\n"));
+ res = SCSI_SCAN_TARGET_PRESENT;
+ goto out_free_result;
+ }
+
res = scsi_add_lun(sdev, result, &bflags);
if (res == SCSI_SCAN_LUN_PRESENT) {
if (bflags & BLIST_KEY) {
-
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