diff options
authorAlan Stern <stern@rowland.harvard.edu>2014-01-30 10:43:22 -0500
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-02-22 12:41:28 -0800
commit5e076f4dcfc7663f4e7b4e8fba88d84f8632f946 (patch)
parentcb5238e402af4fe036bccf05ca94e80c406b6401 (diff)
usb-storage: enable multi-LUN scanning when needed
commit 823d12c95c666fa7ab7dad208d735f6bc6afabdc upstream. People sometimes create their own custom-configured kernels and forget to enable CONFIG_SCSI_MULTI_LUN. This causes problems when they plug in a USB storage device (such as a card reader) with more than one LUN. Fortunately, we can tell fairly easily when a storage device claims to have more than one LUN. When that happens, this patch asks the SCSI layer to probe all the LUNs automatically, regardless of the config setting. The patch also updates the Kconfig help text for usb-storage, explaining that CONFIG_SCSI_MULTI_LUN may be necessary. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Reported-by: Thomas Raschbacher <lordvan@lordvan.com> CC: Matthew Dharm <mdharm-usb@one-eyed-alien.net> CC: James Bottomley <James.Bottomley@HansenPartnership.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2 files changed, 9 insertions, 1 deletions
diff --git a/drivers/usb/storage/Kconfig b/drivers/usb/storage/Kconfig
index 8470e1b114f..1dd0604d191 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'
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 5db15326082..bb7bf198caa 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;