--- x/drivers/media/rc/imon.c
+++ i/drivers/media/rc/imon.c
@@ -536,7 +536,7 @@ static int display_open(struct inode *in
 
 	mutex_lock(&ictx->lock);
 
-	if (!ictx->display_supported) {
+	if (ictx->disconnected || !ictx->display_supported) {
 		pr_err("display not supported by device\n");
 		retval = -ENODEV;
 	} else if (ictx->display_isopen) {
@@ -598,6 +598,10 @@ static int send_packet(struct imon_conte
 	int retval = 0;
 	struct usb_ctrlrequest *control_req = NULL;
 
+	if (ictx->disconnected)
+		return -ENODEV;
+	if (ictx->tx.busy)
+		return -EBUSY;
 	/* Check if we need to use control or interrupt urb */
 	if (!ictx->tx_control) {
 		pipe = usb_sndintpipe(ictx->usbdev_intf0,
@@ -655,6 +659,7 @@ static int send_packet(struct imon_conte
 		}
 		mutex_lock(&ictx->lock);
 
+		ictx->tx.busy = false;
 		retval = ictx->tx.status;
 		if (retval)
 			pr_err_ratelimited("packet tx failed (%d)\n", retval);
@@ -2498,7 +2503,9 @@ static void imon_disconnect(struct usb_i
 	int ifnum;
 
 	ictx = usb_get_intfdata(interface);
+	mutex_lock(&ictx->lock);
 	ictx->disconnected = true;
+	mutex_unlock(&ictx->lock);
 	dev = ictx->dev;
 	ifnum = interface->cur_altsetting->desc.bInterfaceNumber;