See the Device Class Power Management Reference Specification to find out which device power states are defined for a specific device and what the operational requirements are for each state. Not all devices define all the states many devices define only the D0 and D3 states. The exact definitions of the power states are device-specific. Wake-up capability: Can the device request wake-up from this state? In general, if a device can request wake-up from a given power state (for example, D2), it can also request wake-up from any higher-powered state (D1). Only a few types of devices, such as GPUs, have very large hardware contexts that take significantly longer to restore. Restore time: How long does it take to restore the device to the fully operational state? Most types of devices have modest restore times that differ little from one device class to the next. Power consumption: How much power does the device use?ĭevice context: How much of its operational context does the device retain in this state?ĭevice driver behavior: What must the drivers for the device do to restore the device to the fully operational state? Starting with Windows 8, the D3 state is divided into two substates, D3hot and D3cold.ĭevice power states are characterized by the following attributes: The state number is inversely related to power consumption: higher numbered states use less power. D0 is the fully on state, and D1, D2, and D3 are low-power states. Device power states are named D0, D1, D2, and D3. A device power state describes the power state of a device in a computer, independently of the other devices in the computer.
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