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changePowerStateToPriv

Tells a driver's superclass to change the power state of its device.

Declaration

IOReturn changePowerStateToPriv(
 unsigned longordinal );

Parameters

  • ordinal:

    The number of the desired power state in the power state array.

Return Value

A return code that can be ignored by the caller.

Overview

A driver uses this method to tell its superclass to change the power state of the device. This is the recommended way to change the power state of a device. Three things affect driver power state: changePowerStateTo, changePowerStateToPriv, and the desires of the driver's power plane children. Power management puts the device into the maximum state governed by those three entities. Drivers may eliminate the influence of the changePowerStateTo method on power state one of two ways. See powerOverrideOnPriv to ignore the method's influence, or call changePowerStateTo(0) in the driver's start routine to remove the changePowerStateTo method's power request.

See Also

Miscellaneous