* @desc: pointer to the device's struct dvb_usb_device_description.
* @state: initialization and runtime state of the device.
*
+ * @powered: indicated whether the device is power or not.
+ * Powered is in/decremented for each call to modify the state.
* @udev: pointer to the device's struct usb_device.
*
* @usb_mutex: semaphore of USB control messages (reading needs two messages)