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WdfDeviceInitSetPowerPageable method

[Applies to KMDF only]

The WdfDeviceInitSetPowerPageable method informs the power manager that the driver must be able to access pageable data while the system is transitioning between a sleeping state and the working (S0) state.

Syntax


VOID WdfDeviceInitSetPowerPageable(
  [in] PWDFDEVICE_INIT DeviceInit
);

Parameters

DeviceInit [in]

A caller-supplied pointer to a WDFDEVICE_INIT structure.

Return value

None

Remarks

If your function driver or bus driver calls WdfDeviceInitSetPowerPageable, the system ensures that the paging file's device is in its working (D0) state when your driver's device enters a low-power state or returns to its working state. This allows your driver to access files, the registry, and paged pool during your device's power transitions.

By default, the framework enables access to pageable data for function drivers. The framework uses the parent device's setting for each child device that a bus driver enumerates, unless the bus driver calls either WdfDeviceInitSetPowerPageable or WdfDeviceInitSetPowerNotPageable for the child device. If you write a bus driver that calls WdfDeviceInitSetPowerPageable for a child device, no drivers in the child device's stack can call WdfDeviceInitSetPowerNotPageable.

Calling WdfDeviceInitSetPowerPageable or WdfDeviceInitSetPowerNotPageable from a filter driver has no effect. The framework uses the setting that the next-lower driver specifies.

Most drivers do not need to call WdfDeviceInitSetPowerPageable or WdfDeviceInitSetPowerNotPageable. Instead, you should let the framework use the default setting that is appropriate for your driver. However, your driver should call WdfDeviceInitSetPowerNotPageable if the driver is part of a driver stack that must not access pageable data during power transitions (such as the storage stack or the video stack), or if the driver is a bus driver that enumerates devices that might be storage or video devices.

If your driver calls WdfDeviceInitSetPowerInrush, it must not call WdfDeviceInitSetPowerPageable.

Your driver must call WdfDeviceInitSetPowerPageable before it calls WdfDeviceCreate.

For more information about calling WdfDeviceCreate, see Creating a Framework Device Object.

Examples

The following code example informs the power manager that a driver must be able to access pageable data while the system is transitioning between a sleeping state and the working (S0) state.


WdfDeviceInitSetPowerPageable(DeviceInit);

Requirements

Target platform

Universal

Minimum KMDF version

1.0

Header

Wdfdevice.h (include Wdf.h)

Library

Wdf01000.sys (see Framework Library Versioning.)

IRQL

<= DISPATCH_LEVEL

DDI compliance rules

ChildDeviceInitAPI, DeviceInitAPI, DriverCreate, KmdfIrql, KmdfIrql2, PdoDeviceInitAPI

See also

WdfDeviceInitSetPowerNotPageable

 

 

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