The Power Manager is a component that manages device power and improves overall operating system (OS) power efficiency, provides power management for each device, and coexists with applications and drivers that do not support the Power Manager.
You can use power management to reduce the power consumption of a target device and to maintain and preserve the file system in RAM during the reset, on, idle, and suspend power states.
The Power Manager also provides you with the following capabilities:
- A framework in which devices can intelligently manage their own power.
- A mechanism for decoupling the power state of a device from the suspend or resume state of the system.
- A module that has a global view of the system environment, power status and device power states. You can customize the Power Manager to make system-wide decisions about power that are suitable to your platform.
- Control over the code surrounding the call to PowerOffSystem when the system suspends and resumes.
Drivers that support power management should report their capabilities as accurately as possible during enumeration. From then on, they will receive requests from the Power Manager to get or change their device power states. Devices that can manage their own power should use DevicePowerNotify to request that the Power Manager change their device power state.
The Power Manager communicates with devices in a normal thread execution context using calls to DeviceIoControl. This allows device driver writers greater flexibility in handling requests to change device power states.
Last updated on Tuesday, May 18, 2004
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