USB: storage: Never reset devices that will morph to an old mode

Some devices must be switched to a new mode to fully use them.
A reset would make them revert to the old mode. Therefore a reset
must not be used for error handling with such devices.

Signed-off-by: Oliver Neukum <oliver@neukum.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

2 files changed, 8 insertions, 1 deletions

diff --git a/drivers/usb/core/quirks.c b/drivers/usb/core/quirks.c
index ab93918d9207..0b689224394b 100644
--- a/drivers/usb/core/quirks.c
+++ b/drivers/usb/core/quirks.c
@@ -120,6 +120,7 @@ void usb_detect_quirks(struct usb_device *udev)
          * for all devices.  It will affect things like hub resets
          * and EMF-related port disables.
          */
-        udev->persist_enabled = 1;
+        if (!(udev->quirks & USB_QUIRK_RESET_MORPHS))
+                udev->persist_enabled = 1;
 #endif  /* CONFIG_PM */
 }
diff --git a/drivers/usb/storage/transport.c b/drivers/usb/storage/transport.c
index cc313d16d727..468038126e5e 100644
--- a/drivers/usb/storage/transport.c
+++ b/drivers/usb/storage/transport.c
@@ -47,6 +47,8 @@
 #include <linux/errno.h>
 #include <linux/slab.h>
 
+#include <linux/usb/quirks.h>
+
 #include <scsi/scsi.h>
 #include <scsi/scsi_eh.h>
 #include <scsi/scsi_device.h>
@@ -1297,6 +1299,10 @@ int usb_stor_port_reset(struct us_data *us)
 {
         int result;
 
+        /*for these devices we must use the class specific method */
+        if (us->pusb_dev->quirks & USB_QUIRK_RESET_MORPHS)
+                return -EPERM;
+
         result = usb_lock_device_for_reset(us->pusb_dev, us->pusb_intf);
         if (result < 0)
                 US_DEBUGP("unable to lock device for reset: %d\n", result);