diff --git a/drivers/staging/comedi/drivers/vmk80xx.c b/drivers/staging/comedi/drivers/vmk80xx.c
index 65dc6c51037e..ef4810902890 100644
--- a/drivers/staging/comedi/drivers/vmk80xx.c
+++ b/drivers/staging/comedi/drivers/vmk80xx.c
@@ -222,6 +222,9 @@ static int vmk80xx_reset_device(struct comedi_device *dev)
 	int retval;
 
 	size = usb_endpoint_maxp(devpriv->ep_tx);
+
+	if(!size)
+		return -EINVAL;
 	memset(devpriv->usb_tx_buf, 0, size);
 	retval = vmk80xx_write_packet(dev, VMK8055_CMD_RST);
 	if (retval)