Power Manager and ACPI/APM

Windows CE .NET

The Power Manager is not related to the Advanced Configuration and Power Interface (ACPI) or Advanced Power Management (APM) power management mechanisms. The ACPI specification defines a linear set of OS power states ranging from high-power/high-function to low-power/low-function. The Windows CE Power Manager allows OEMs to define any number of OS power states and does not require that they be linearly ordered.

You are encouraged to define OS power states that are situational and will control device power based on its location or environment. For example, you might define OS power states such that certain devices are turned off if the unit is not in a cradle or allow devices to run at a high power consumption level if the OS is connected to wall power. Similarly, you could define different idle or suspend states based on the OS's environment. You are responsible for customizing the Power Manager to recognize when transitioning between these states is appropriate or necessary.

System power states are significantly different from the ACPI model. However, device power states are superficially similar to ACPI device power states, although there are some subtle differences. For example, the D3 power state is assumed to have semantics related to a given device's ability to act as a wake source when the OS as a whole is suspended.

See Also

System Power States | Power Management Architecture

 Last updated on Tuesday, May 18, 2004

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