Apple's US patent 8,990,598 on power management

The first claim of US '598:

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1. A method affecting a power state transition at a computer having a plurality of component devices, the method comprising: at a power manager of the computer: receiving an input power requirement for at least one device of the plurality of component devices from a power management client; storing a value associated with the received input power requirement; determining when the stored value is different from a current power state value for the at least one device maintained by the power manager; and in response to determining, setting the current power state value for the at least one device maintained by the power manager to the stored value.

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