1 files changed, 26 insertions, 18 deletions

diff --git a/drivers/usb/serial/qcserial.c b/drivers/usb/serial/qcserial.c
index 7556f343c0f3..a9c4dc4eb05f 100644
--- a/drivers/usb/serial/qcserial.c
+++ b/drivers/usb/serial/qcserial.c
@@ -143,14 +143,13 @@ static int qcprobe(struct usb_serial *serial, const struct usb_device_id *id)
 
         spin_lock_init(&data->susp_lock);
 
-        switch (nintf) {
-        case 1:
+        if (nintf == 1) {
                 /* QDL mode */
                 /* Gobi 2000 has a single altsetting, older ones have two */
                 if (serial->interface->num_altsetting == 2)
                         intf = &serial->interface->altsetting[1];
                 else if (serial->interface->num_altsetting > 2)
-                        break;
+                        goto done;
 
                 if (intf->desc.bNumEndpoints == 2 &&
                     usb_endpoint_is_bulk_in(&intf->endpoint[0].desc) &&
@@ -162,10 +161,18 @@ static int qcprobe(struct usb_serial *serial, const struct usb_device_id *id)
                         else
                                 altsetting = 1;
                 }
-                break;
+                goto done;
 
-        case 3:
-        case 4:
+        }
+
+        if (nintf < 3 || nintf > 4) {
+                dev_err(dev, "unknown number of interfaces: %d\n", nintf);
+                goto done;
+        }
+
+        /* default to enabling interface */
+        altsetting = 0;
+        switch (ifnum) {
                 /* Composite mode; don't bind to the QMI/net interface as that
                  * gets handled by other drivers.
                  */
@@ -183,27 +190,28 @@ static int qcprobe(struct usb_serial *serial, const struct usb_device_id *id)
                  * 3: NMEA
                  */
 
-                if (ifnum == 1 && !is_gobi1k) {
+        case 1:
+                if (is_gobi1k)
+                        altsetting = -1;
+                else
                         dev_dbg(dev, "Gobi 2K+ DM/DIAG interface found\n");
-                        altsetting = 0;
-                } else if (ifnum == 2) {
-                        dev_dbg(dev, "Modem port found\n");
-                        altsetting = 0;
-                } else if (ifnum==3 && !is_gobi1k) {
+                break;
+        case 2:
+                dev_dbg(dev, "Modem port found\n");
+                break;
+        case 3:
+                if (is_gobi1k)
+                        altsetting = -1;
+                else
                         /*
                          * NMEA (serial line 9600 8N1)
                          * # echo "\$GPS_START" > /dev/ttyUSBx
                          * # echo "\$GPS_STOP"  > /dev/ttyUSBx
                          */
                         dev_dbg(dev, "Gobi 2K+ NMEA GPS interface found\n");
-                        altsetting = 0;
-                }
-                break;
-
-        default:
-                dev_err(dev, "unknown number of interfaces: %d\n", nintf);
         }
 
+done:
         if (altsetting >= 0) {
                 retval = usb_set_interface(serial->dev, ifnum, altsetting);
                 if (retval < 0) {