Responding to Power State Changes
The most basic level of power management support that a driver can implement is to opt-in to receive notifications for changes to the overall system power state. These include notifications before the system is put to sleep and a notification when the system wakes from sleep. This is particularly important for the driver of a PCI device, since these notifications need to be handled to allow the PCI bus to be powered down completely during system sleep.
The I/O Kit's power model is unique in that the framework doesn't dictate the set of power states that a driver must implement; rather a driver defines its own list of power states that match the capabilities of the device that it controls. At the very least, a ...
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