[3.19.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-3.19.y-queue branch of the 3.19.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.19.y-queue

This patch is scheduled to be released in version 3.19.8-ckt12.

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

For more information about the 3.19.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From ca45972270583e1f0fd4a959ede39faa898ebd37 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 | 54 +++++++++++++++++++++++++++----------------
 1 file changed, 34 insertions(+), 20 deletions(-)

diff --git a/drivers/usb/serial/qcserial.c b/drivers/usb/serial/qcserial.c
index 1d7a2a4..514fa91 100644
--- a/drivers/usb/serial/qcserial.c
+++ b/drivers/usb/serial/qcserial.c
@@ -212,6 +212,10 @@ static int qcprobe(struct usb_serial *serial, const struct usb_device_id *id)
 	__u8 ifnum;
 	int altsetting = -1;

+	/* 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;
@@ -337,29 +341,39 @@ static int qcprobe(struct usb_serial *serial, const struct usb_device_id *id)
 		break;
 	case QCSERIAL_HWI:
 		/*
-		 * Huawei layout:
-		 * 0: AT-capable modem port
-		 * 1: DM/DIAG
-		 * 2: AT-capable modem port
-		 * 3: CCID-compatible PCSC interface
-		 * 4: QMI/net
-		 * 5: NMEA
+		 * Huawei devices map functions by subclass + protocol
+		 * instead of interface numbers. The protocol identify
+		 * a specific function, while the subclass indicate a
+		 * specific firmware source
+		 *
+		 * This is a blacklist of functions known to be
+		 * non-serial.  The rest are assumed to be serial and
+		 * will be handled by this driver
 		 */
-		switch (ifnum) {
-		case 0:
-		case 2:
-			dev_dbg(dev, "Modem port found\n");
-			break;
-		case 1:
-			dev_dbg(dev, "DM/DIAG interface found\n");
-			break;
-		case 5:
-			dev_dbg(dev, "NMEA GPS interface found\n");
-			break;
-		default:
-			/* don't claim any unsupported interface */
+		switch (intf->desc.bInterfaceProtocol) {
+			/* QMI combined (qmi_wwan) */
+		case 0x07:
+		case 0x37:
+		case 0x67:
+			/* QMI data (qmi_wwan) */
+		case 0x08:
+		case 0x38:
+		case 0x68:
+			/* QMI control (qmi_wwan) */
+		case 0x09:
+		case 0x39:
+		case 0x69:
+			/* NCM like (huawei_cdc_ncm) */
+		case 0x16:
+		case 0x46:
+		case 0x76:
 			altsetting = -1;
 			break;
+		default:
+			dev_dbg(dev, "Huawei type serial port found (%02x/%02x/%02x)\n",
+				intf->desc.bInterfaceClass,
+				intf->desc.bInterfaceSubClass,
+				intf->desc.bInterfaceProtocol);
 		}
 		break;
 	default:
--
1.9.1