diff --git a/drivers/usb/serial/sierra.c b/drivers/usb/serial/sierra.c
index 5019325..c5c41ae 100644
--- a/drivers/usb/serial/sierra.c
+++ b/drivers/usb/serial/sierra.c
@@ -16,8 +16,9 @@
   Portions based on the option driver by Matthias Urlichs <smurf@smurf.noris.de>
   Whom based his on the Keyspan driver by Hugh Blemings <hugh@blemings.org>
 */
-
-#define DRIVER_VERSION "v.1.3.8"
+/* Uncomment to log function calls */
+/* #define DEBUG */
+#define DRIVER_VERSION "v.1.7.16"
 #define DRIVER_AUTHOR "Kevin Lloyd, Elina Pasheva, Matthew Safar, Rory Filer"
 #define DRIVER_DESC "USB Driver for Sierra Wireless USB modems"
 
@@ -33,8 +34,10 @@
 #define SWIMS_USB_REQUEST_SetPower	0x00
 #define SWIMS_USB_REQUEST_SetNmea	0x07
 
-#define N_IN_URB	8
-#define N_OUT_URB	64
+#define N_IN_URB_HM	8
+#define N_OUT_URB_HM	64
+#define N_IN_URB	4
+#define N_OUT_URB	4
 #define IN_BUFLEN	4096
 
 #define MAX_TRANSFER		(PAGE_SIZE - 512)
@@ -124,6 +127,23 @@
 	return 0;
 }
 
+static int is_himemory(const u8 ifnum,
+				const struct sierra_iface_info *himemorylist)
+{
+	const u8  *info;
+	int i;
+
+	if (himemorylist) {
+		info = himemorylist->ifaceinfo;
+
+		for (i=0; i < himemorylist->infolen; i++) {
+			if (info[i] == ifnum)
+				return 1;
+		}
+	}
+	return 0;
+}
+
 static int sierra_calc_interface(struct usb_serial *serial)
 {
 	int interface;
@@ -186,6 +206,20 @@
 	return result;
 }
 
+/* interfaces with higher memory requirements */
+static const u8 hi_memory_typeA_ifaces[] = { 0, 2 };
+static const struct sierra_iface_info typeA_interface_list = {
+	.infolen = ARRAY_SIZE(hi_memory_typeA_ifaces),
+	.ifaceinfo = hi_memory_typeA_ifaces,
+};
+
+static const u8 hi_memory_typeB_ifaces[] = { 3, 4, 5, 6 };
+static const struct sierra_iface_info typeB_interface_list = {
+	.infolen = ARRAY_SIZE(hi_memory_typeB_ifaces),
+	.ifaceinfo = hi_memory_typeB_ifaces,
+};
+
+/* 'blacklist' of interfaces not served by this driver */
 static const u8 direct_ip_non_serial_ifaces[] = { 7, 8, 9, 10, 11 };
 static const struct sierra_iface_info direct_ip_interface_blacklist = {
 	.infolen = ARRAY_SIZE(direct_ip_non_serial_ifaces),
@@ -286,8 +320,10 @@
 	struct usb_anchor active;
 	struct usb_anchor delayed;
 
+	int num_out_urbs;
+	int num_in_urbs;
 	/* Input endpoints and buffers for this port */
-	struct urb *in_urbs[N_IN_URB];
+	struct urb *in_urbs[N_IN_URB_HM];
 
 	/* Settings for the port */
 	int rts_state;	/* Handshaking pins (outputs) */
@@ -460,7 +496,7 @@
 	spin_lock_irqsave(&portdata->lock, flags);
 	dev_dbg(&port->dev, "%s - outstanding_urbs: %d\n", __func__,
 		portdata->outstanding_urbs);
-	if (portdata->outstanding_urbs > N_OUT_URB) {
+	if (portdata->outstanding_urbs > portdata->num_out_urbs) {
 		spin_unlock_irqrestore(&portdata->lock, flags);
 		dev_dbg(&port->dev, "%s - write limit hit\n", __func__);
 		return 0;
@@ -665,7 +701,7 @@
 	/* try to give a good number back based on if we have any free urbs at
 	 * this point in time */
 	spin_lock_irqsave(&portdata->lock, flags);
-	if (portdata->outstanding_urbs > N_OUT_URB * 2 / 3) {
+	if (portdata->outstanding_urbs > (portdata->num_out_urbs * 2) / 3) {
 		spin_unlock_irqrestore(&portdata->lock, flags);
 		dev_dbg(&port->dev, "%s - write limit hit\n", __func__);
 		return 0;
@@ -680,7 +716,7 @@
 	int i;
 	struct sierra_port_private *portdata = usb_get_serial_port_data(port);
 
-	for (i = 0; i < ARRAY_SIZE(portdata->in_urbs); i++)
+	for (i = 0; i < portdata->num_in_urbs; i++)
 		usb_kill_urb(portdata->in_urbs[i]);
 
 	usb_kill_urb(port->interrupt_in_urb);
@@ -695,7 +731,7 @@
 	struct sierra_port_private *portdata = usb_get_serial_port_data(port);
 
 	ok_cnt = 0;
-	for (i = 0; i < ARRAY_SIZE(portdata->in_urbs); i++) {
+	for (i = 0; i < portdata->num_in_urbs; i++) {
 		urb = portdata->in_urbs[i];
 		if (!urb)
 			continue;
@@ -791,7 +827,7 @@
 		/* Stop reading urbs */
 		sierra_stop_rx_urbs(port);
 		/* .. and release them */
-		for (i = 0; i < N_IN_URB; i++) {
+		for (i = 0; i < portdata->num_in_urbs; i++) {
 			sierra_release_urb(portdata->in_urbs[i]);
 			portdata->in_urbs[i] = NULL;
 		}
@@ -818,7 +854,7 @@
 
 
 	endpoint = port->bulk_in_endpointAddress;
-	for (i = 0; i < ARRAY_SIZE(portdata->in_urbs); i++) {
+	for (i = 0; i < portdata->num_in_urbs; i++) {
 		urb = sierra_setup_urb(serial, endpoint, USB_DIR_IN, port,
 					IN_BUFLEN, GFP_KERNEL,
 					sierra_indat_callback);
@@ -869,7 +905,9 @@
 {
 	struct usb_serial_port *port;
 	struct sierra_port_private *portdata;
+	struct sierra_iface_info *himemoryp = NULL;
 	int i;
+	u8 ifnum;
 
 	dev_dbg(&serial->dev->dev, "%s\n", __func__);
 
@@ -886,13 +924,40 @@
 		portdata = kzalloc(sizeof(*portdata), GFP_KERNEL);
 		if (!portdata) {
 			dev_dbg(&port->dev, "%s: kmalloc for "
-				"sierra_port_private (%d) failed!.\n",
+				"sierra_port_private (%d) failed!\n",
 				__func__, i);
 			return -ENOMEM;
 		}
 		spin_lock_init(&portdata->lock);
 		init_usb_anchor(&portdata->active);
 		init_usb_anchor(&portdata->delayed);
+		ifnum = i;
+		/* Assume low memory requirements */
+		portdata->num_out_urbs = N_OUT_URB;
+		portdata->num_in_urbs  = N_IN_URB;
+
+		/* Determine actual memory requirements */
+		if (serial->num_ports == 1) {
+			/* Get interface number for composite device */
+			ifnum = sierra_calc_interface(serial);
+			himemoryp =
+			    (struct sierra_iface_info *)&typeB_interface_list;
+			if (is_himemory(ifnum, himemoryp)) {
+				portdata->num_out_urbs = N_OUT_URB_HM;
+				portdata->num_in_urbs  = N_IN_URB_HM;
+			}
+		}
+		else {
+			himemoryp =
+			    (struct sierra_iface_info *)&typeA_interface_list;
+			if (is_himemory(i, himemoryp)) {
+				portdata->num_out_urbs = N_OUT_URB_HM;
+				portdata->num_in_urbs  = N_IN_URB_HM;
+			}
+		}
+		dev_dbg(&serial->dev->dev,
+			"Memory usage (urbs) interface #%d, in=%d, out=%d\n",
+			ifnum,portdata->num_in_urbs, portdata->num_out_urbs );
 		/* Set the port private data pointer */
 		usb_set_serial_port_data(port, portdata);
 	}