[4.2.y-ckt stable] Patch "USB: qcserial: Fix support for HP lt4112 LTE/HSPA+ Gobi 4G Modem" has been added to staging queue

[Kamal Mostafa]

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

    USB: qcserial: Fix support for HP lt4112 LTE/HSPA+ Gobi 4G Modem

to the linux-4.2.y-queue branch of the 4.2.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-4.2.y-queue

This patch is scheduled to be released in version 4.2.8-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 4.2.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

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>From be5c617b501a1ca3c9e2634ec75d0a6a9259f801 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bj=C3=B8rn=20Mork?= <bjorn at mork.no>
Date: Mon, 16 Nov 2015 13:15:46 +0100
Subject: USB: qcserial: Fix support for HP lt4112 LTE/HSPA+ Gobi 4G Modem
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

commit 59536da34513c594af2a6fd35ba65ea45b6960a1 upstream.

The DEVICE_HWI type was added under the faulty assumption that Huawei
devices based on Qualcomm chipsets and firmware use the static USB
interface numbering known from Gobi devices.  But this model does
not apply to Huawei devices like the HP branded lt4112 (Huawei me906e).
Huawei firmwares will dynamically assign interface numbers. Functions
are renumbered when the firmware is reconfigured.

Fix by changing the DEVICE_HWI type to use a simplified version
of Huawei's subclass + protocol scheme: Blacklisting known network
interface combinations and assuming the rest are serial.

Reported-and-tested-by: Muri Nicanor <muri+libqmi at immerda.ch>
Tested-by: Martin Hauke <mardnh at gmx.de>
Fixes: e7181d005e84 ("USB: qcserial: Add support for HP lt4112 LTE/HSPA+ Gobi 4G Modem")
Signed-off-by: Bjørn Mork <bjorn at mork.no>
Signed-off-by: Johan Hovold <johan at kernel.org>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/usb/serial/qcserial.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/usb/serial/qcserial.c b/drivers/usb/serial/qcserial.c
index 514fa91..293b27a 100644
--- a/drivers/usb/serial/qcserial.c
+++ b/drivers/usb/serial/qcserial.c
@@ -216,6 +216,10 @@ static int qcprobe(struct usb_serial *serial, const struct usb_device_id *id)
 	if (intf->desc.bInterfaceClass != USB_CLASS_VENDOR_SPEC)
 		goto done;

+	/* we only support vendor specific functions */
+	if (intf->desc.bInterfaceClass != USB_CLASS_VENDOR_SPEC)
+		goto done;
+
 	nintf = serial->dev->actconfig->desc.bNumInterfaces;
 	dev_dbg(dev, "Num Interfaces = %d\n", nintf);
 	ifnum = intf->desc.bInterfaceNumber;
--
1.9.1