>From ff39d073bda410d032d17711a7deb1761f451bae Mon Sep 17 00:00:00 2001
From: Oliver Neukum <oliver@xxxxxxxxxx>
Date: Mon, 14 Dec 2009 17:59:11 +0100
Subject: [PATCH 1/2] 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@xxxxxxxxxx>
---
drivers/usb/core/quirks.c | 3 ++-
drivers/usb/storage/transport.c | 6 ++++++
include/linux/usb/quirks.h | 3 +++
3 files changed, 11 insertions(+), 1 deletions(-)
diff --git a/drivers/usb/core/quirks.c b/drivers/usb/core/quirks.c
index ab93918..0b68922 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 cc313d1..4680381 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);
diff --git a/include/linux/usb/quirks.h b/include/linux/usb/quirks.h
index 2526f3b..0a555dd 100644
--- a/include/linux/usb/quirks.h
+++ b/include/linux/usb/quirks.h
@@ -19,4 +19,7 @@
/* device can't handle its Configuration or Interface strings */
#define USB_QUIRK_CONFIG_INTF_STRINGS 0x00000008
+/*device will morph if reset, don't use reset for handling errors */
+#define USB_QUIRK_RESET_MORPHS 0x00000010
+
#endif /* __LINUX_USB_QUIRKS_H */
--
1.6.4.2
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