Some non-standard SCSI targets or protocols, such as USB UFI, report "no
LUN present" by setting the Peripheral Device Type to 0x1f and the
Peripheral Qualifier to 0 (not 3 as the standard requires) in the INQUIRY
response. This patch (as650b) adds a new target flag and code to
accomodate such targets.
Signed-off-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
---
This is a revised version of an earlier patch. By adding a new flag to
the target structure, this version can avoid any conflicts with devices
that use PDT = 0x1f to represent a legitimate LUN.
After this patch has been merged, I will add code to the usb-storage
slave_alloc routine to set the pdt_1f_for_no_lun flag for all devices
using the UFI protocol.
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 targets 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 (starget->pdt_1f_for_no_lun && (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) {
Index: usb-2.6/include/scsi/scsi_device.h
===================================================================
--- usb-2.6.orig/include/scsi/scsi_device.h
+++ usb-2.6/include/scsi/scsi_device.h
@@ -167,7 +167,10 @@ struct scsi_target {
unsigned int channel;
unsigned int id; /* target id ... replace
* scsi_device.id eventually */
- unsigned long create:1; /* signal that it needs to be added */
+ unsigned int create:1; /* signal that it needs to be added */
+ unsigned int pdt_1f_for_no_lun; /* PDT = 0x1f */
+ /* means no lun present */
+
char scsi_level;
void *hostdata; /* available to low-level driver */
unsigned long starget_data[0]; /* for the transport */
-
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