System Power State Transitions

  • Article

The Power Manager makes system power state transitions under the following circumstances:

  • An OEM-specific event occurs that requires a state change.
  • An application calls SetSystemPowerState

OEM-specific events might include going from AC power to battery power, prolonged periods of system inactivity, insertion into a cradle, low battery levels, and so on. The OEM is responsible for customizing the Power Manager to recognize when transitions between system power states are appropriate and for carrying them out when necessary. The base Power manager sources included with Platform Builder recognize changes AC-to-battery power transitions.

Applications can call SetSystemPowerState with an explicit power state name or a set bit as to the type of system power state they would like to enter. Applications that have OEM-specific knowledge of system power states may choose to use explicit power state names. Platform-independent applications will generally set bits instead and allow the Power Manager to determine which OEM-specific power state maps best to the hint. The Power Manager may restrict the states that applications may request using SetSystemPowerState.

See Also

System Power State Transitions

 Last updated on Tuesday, May 18, 2004

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