diff --git a/drivers/usb/serial/ipaq.c b/drivers/usb/serial/ipaq.c
index 24fcc64b837..d6231c38813 100644
--- a/drivers/usb/serial/ipaq.c
+++ b/drivers/usb/serial/ipaq.c
@@ -966,6 +966,15 @@ static int ipaq_calc_num_ports(struct usb_serial *serial)
 static int ipaq_startup(struct usb_serial *serial)
 {
 	dbg("%s", __func__);
+
+	/* Some of the devices in ipaq_id_table[] are composite, and we
+	 * shouldn't bind to all the interfaces.  This test will rule out
+	 * some obviously invalid possibilities.
+	 */
+	if (serial->num_bulk_in < serial->num_ports ||
+			serial->num_bulk_out < serial->num_ports)
+		return -ENODEV;
+
 	if (serial->dev->actconfig->desc.bConfigurationValue != 1) {
 		/*
 		 * FIXME: HP iPaq rx3715, possibly others, have 1 config that