Handling a System Query-Power IRP in a Bus Driver

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When a system query-power request reaches a bus driver (that is not the power policy owner for a device), the driver ensures that it can support a device power state that corresponds to the queried system power state and, if wake-up is enabled, that the queried system power state would not prevent its device from waking the system.

In Windows 7 and Windows Vista, the bus driver sets Irp->IoStatus.Status to STATUS_SUCCESS if the driver can change to the specified power state or sets a failure status if the driver cannot.

In Windows Server 2003, Windows XP, and Windows 2000, the bus driver first calls PoStartNextPowerIrp and then sets Irp->IoStatus.Status to STATUS_SUCCESS if the driver can change to the specified power state or sets a failure status if the driver cannot.

After the bus driver completes the IRP, the power manager calls IoCompletion routines set by other drivers as they passed the IRP down the stack.