qcserial: bind to DM/DIAG port on Gobi 1K devices

Turns out we just need altsetting 1 and then we can talk to it.

Signed-off-by: Dan Williams <dcbw@redhat.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 5 insertions, 2 deletions

diff --git a/drivers/usb/serial/qcserial.c b/drivers/usb/serial/qcserial.c
index 24662547dc5b..59b32b782126 100644
--- a/drivers/usb/serial/qcserial.c
+++ b/drivers/usb/serial/qcserial.c
@@ -197,12 +197,15 @@ static int qcprobe(struct usb_serial *serial, const struct usb_device_id *id)
 
         if (is_gobi1k) {
                 /* Gobi 1K USB layout:
-                 * 0: serial port (doesn't respond)
+                 * 0: DM/DIAG (use libqcdm from ModemManager for communication)
                  * 1: serial port (doesn't respond)
                  * 2: AT-capable modem port
                  * 3: QMI/net
                  */
-                if (ifnum == 2)
+                if (ifnum == 0) {
+                        dev_dbg(dev, "Gobi 1K DM/DIAG interface found\n");
+                        altsetting = 1;
+                } else if (ifnum == 2)
                         dev_dbg(dev, "Modem port found\n");
                 else
                         altsetting = -1;