It is receiving full power from the system and is delivering full functionality to the user. Buses in D1 cannot do anything to the bus that would force devices on that bus to lose context. Attains greater power savings than D1. Devices in D2 must be prepared for the bus to be in D2 or higher. State in which device is off and not running.
Device context is lost.
Power can be removed from the device. Any device context lost must be restored by the device driver when returning the device to the D0 state. Default Power State Definitions D0 Device is on and running. It is receiving full power from the system, and is delivering full functionality to the user. This state is not defined and not used by the default device class.