[3.16.y-ckt stable] Patch "USB: core: add device-qualifier quirk" has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    USB: core: add device-qualifier quirk

to the linux-3.16.y-queue branch of the 3.16.y-ckt extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.16.y-queue

This patch is scheduled to be released in version 3.16.7-ckt2.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.16.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

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>From 41097a382019cfddfc810a79b3739ea1eb2937bb Mon Sep 17 00:00:00 2001
From: Johan Hovold <johan at kernel.org>
Date: Mon, 25 Aug 2014 17:51:26 +0200
Subject: USB: core: add device-qualifier quirk
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

commit 2a159389bf5d962359349a76827b2f683276a1c7 upstream.

Add new quirk for devices that cannot handle requests for the
device_qualifier descriptor.

A USB-2.0 compliant device must respond to requests for the
device_qualifier descriptor (even if it's with a request error), but at
least one device is known to misbehave after such a request.

Suggested-by: Bjørn Mork <bjorn at mork.no>
Signed-off-by: Johan Hovold <johan at kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
[ luis: prereq for the following Elan touchscreen patches ]
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/usb/core/hub.c     | 3 +++
 include/linux/usb/quirks.h | 3 +++
 2 files changed, 6 insertions(+)

diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index ba2a8f3b8059..0e0e0354c523 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -4524,6 +4524,9 @@ check_highspeed (struct usb_hub *hub, struct usb_device *udev, int port1)
 	struct usb_qualifier_descriptor	*qual;
 	int				status;

+	if (udev->quirks & USB_QUIRK_DEVICE_QUALIFIER)
+		return;
+
 	qual = kmalloc (sizeof *qual, GFP_KERNEL);
 	if (qual == NULL)
 		return;
diff --git a/include/linux/usb/quirks.h b/include/linux/usb/quirks.h
index 49587dc22f5d..8b96ae2a38fe 100644
--- a/include/linux/usb/quirks.h
+++ b/include/linux/usb/quirks.h
@@ -33,4 +33,7 @@
 /* device generates spurious wakeup, ignore remote wakeup capability */
 #define USB_QUIRK_IGNORE_REMOTE_WAKEUP	0x00000200

+/* device can't handle device_qualifier descriptor requests */
+#define USB_QUIRK_DEVICE_QUALIFIER	0x00000100
+
 #endif /* __LINUX_USB_QUIRKS_H */
--
2.1.0