iokit/IOKit/IOService.h

309     // TRUE once PMinit has been called
1332 /*! @function PMinit
1334     @discussion <code>PMinit</code> allocates and initializes the power management instance variables, and it should be called before accessing those variables or calling the power management methods. This method should be called inside the driver's <code>start</code> routine and must be paired with a call to @link PMstop PMstop@/link.
1335     Most calls to <code>PMinit</code> are followed by calls to @link joinPMtree joinPMtree@/link and @link registerPowerDriver registerPowerDriver@/link. */
1337     virtual void PMinit( void );
1342     Calling <code>PMstop</code> cleans up for the three power management initialization calls: @link PMinit PMinit@/link, @link joinPMtree joinPMtree@/link, and @link registerPowerDriver registerPowerDriver@/link. */
1348     @discussion A driver uses this method to call its nub when initializing (usually in its <code>start</code> routine after calling @link PMinit PMinit@/link), to be attached into the power management hierarchy (i.e., the power plane). A driver usually calls this method on the driver for the device that provides it power (this is frequently the nub).
1600     Calls to @link PMinit PMinit@/link and @link registerPowerDriver registerPowerDriver@/link enable power management to change a device's power state using <code>setPowerState</code>. <code>setPowerState</code> is called in a clean and separate thread context.