Input: bcm5974 - switch back to normal mode when closing

Staying in multi-touch mode after closing the device sometimes makes
the keyboard drop keys or repeat keys irratically. The conjecture is
that some internal buffer starts to overflow, resulting in undefined
behavior. Switching back to normal mode when closing the device makes
the problem go away.
Signed-off-by: Henrik Rydberg <rydberg@euromail.se>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

drivers/input/mouse/bcm5974.c

@@ -351,8 +351,9 @@ static int report_tp_state(struct bcm5974 *dev, int size)
 #define BCM5974_WELLSPRING_MODE_REQUEST_VALUE		0x300
 #define BCM5974_WELLSPRING_MODE_REQUEST_INDEX		0
 #define BCM5974_WELLSPRING_MODE_VENDOR_VALUE		0x01
+#define BCM5974_WELLSPRING_MODE_NORMAL_VALUE		0x08
 
-static int bcm5974_wellspring_mode(struct bcm5974 *dev)
+static int bcm5974_wellspring_mode(struct bcm5974 *dev, bool on)
 {
 	char *data = kmalloc(8, GFP_KERNEL);
 	int retval = 0, size;
@@ -377,7 +378,9 @@ static int bcm5974_wellspring_mode(struct bcm5974 *dev)
 	}
 
 	/* apply the mode switch */
-	data[0] = BCM5974_WELLSPRING_MODE_VENDOR_VALUE;
+	data[0] = on ?
+		BCM5974_WELLSPRING_MODE_VENDOR_VALUE :
+		BCM5974_WELLSPRING_MODE_NORMAL_VALUE;
 
 	/* write configuration */
 	size = usb_control_msg(dev->udev, usb_sndctrlpipe(dev->udev, 0),
@@ -392,7 +395,8 @@ static int bcm5974_wellspring_mode(struct bcm5974 *dev)
 		goto out;
 	}
 
-	dprintk(2, "bcm5974: switched to wellspring mode.\n");
+	dprintk(2, "bcm5974: switched to %s mode.\n",
+		on ? "wellspring" : "normal");
 
  out:
 	kfree(data);
@@ -481,7 +485,7 @@ static void bcm5974_irq_trackpad(struct urb *urb)
  */
 static int bcm5974_start_traffic(struct bcm5974 *dev)
 {
-	if (bcm5974_wellspring_mode(dev)) {
+	if (bcm5974_wellspring_mode(dev, true)) {
 		dprintk(1, "bcm5974: mode switch failed\n");
 		goto error;
 	}
@@ -504,6 +508,7 @@ static void bcm5974_pause_traffic(struct bcm5974 *dev)
 {
 	usb_kill_urb(dev->tp_urb);
 	usb_kill_urb(dev->bt_urb);
+	bcm5974_wellspring_mode(dev, false);
 }
 
 /*