2 files changed, 9 insertions, 1 deletions

diff --git a/drivers/usb/storage/Kconfig b/drivers/usb/storage/Kconfig
index 8470e1b114f2..1dd0604d1911 100644
--- a/drivers/usb/storage/Kconfig
+++ b/drivers/usb/storage/Kconfig
@@ -18,7 +18,9 @@ config USB_STORAGE
 
           This option depends on 'SCSI' support being enabled, but you
           probably also need 'SCSI device support: SCSI disk support'
-          (BLK_DEV_SD) for most USB storage devices.
+          (BLK_DEV_SD) for most USB storage devices.  Some devices also
+          will require 'Probe all LUNs on each SCSI device'
+          (SCSI_MULTI_LUN).
 
           To compile this driver as a module, choose M here: the
           module will be called usb-storage.
diff --git a/drivers/usb/storage/scsiglue.c b/drivers/usb/storage/scsiglue.c
index 18509e6c21ab..9d38ddc8da49 100644
--- a/drivers/usb/storage/scsiglue.c
+++ b/drivers/usb/storage/scsiglue.c
@@ -78,6 +78,8 @@ 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
@@ -102,6 +104,10 @@ static int slave_alloc (struct scsi_device *sdev)
          */
         blk_queue_update_dma_alignment(sdev->request_queue, (512 - 1));
 
+        /* Tell the SCSI layer if we know there is more than one LUN */
+        if (us->protocol == USB_PR_BULK && us->max_lun > 0)
+                sdev->sdev_bflags |= BLIST_FORCELUN;
+
         return 0;
 }