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EvtDeviceDisarmWakeFromSx function

[Applies to KMDF and UMDF]

A driver's EvtDeviceDisarmWakeFromSx event callback function disarms (that is, disables) a device's ability to trigger a wake signal while the device and system are in low-power states.

Syntax


EVT_WDF_DEVICE_DISARM_WAKE_FROM_SX EvtDeviceDisarmWakeFromSx;

VOID EvtDeviceDisarmWakeFromSx(
  _In_  WDFDEVICE Device
)
{ ... }

Parameters

Device [in]

A handle to a framework device object.

Return value

None

Remarks

To register an EvtDeviceDisarmWakeFromSx callback function, a driver must call WdfDeviceInitSetPowerPolicyEventCallbacks.

If the driver has registered this callback function, the framework calls it after the framework has determined that system power is being restored, and after the bus driver completes the wait/wake IRP. Before calling the driver's EvtDeviceDisarmWakeFromSx callback function, the framework calls the driver's EvtDeviceD0Entry, EvtInterruptEnable, and EvtDeviceWakeFromSxTriggered callback functions.

The EvtDeviceDisarmWakeFromSx callback function must perform any hardware operations that are needed to disable the device's ability to trigger a wake signal after the power has been lowered.

For more information about when the framework calls this callback function, see PnP and Power Management Scenarios.

For more information about this callback function, see Supporting System Wake-Up.

The EvtDeviceDisarmWakeFromSx callback function is called at IRQL = PASSIVE_LEVEL. You should not make this callback function pageable.

Examples

To define an EvtDeviceDisarmWakeFromSx callback function, you must first provide a function declaration that identifies the type of callback function you’re defining. Windows provides a set of callback function types for drivers. Declaring a function using the callback function types helps Code Analysis for Drivers, Static Driver Verifier (SDV), and other verification tools find errors, and it’s a requirement for writing drivers for the Windows operating system.

For example, to define an EvtDeviceDisarmWakeFromSx callback function that is named MyDeviceDisarmWakeFromSx, use the EVT_WDF_DEVICE_DISARM_WAKE_FROM_SX type as shown in this code example:


EVT_WDF_DEVICE_DISARM_WAKE_FROM_SX  MyDeviceDisarmWakeFromSx;

Then, implement your callback function as follows:


_Use_decl_annotations_
VOID
 MyDeviceDisarmWakeFromSx (
    WDFDEVICE  Device
    )
  {...}

The EVT_WDF_DEVICE_DISARM_WAKE_FROM_SX function type is defined in the Wdfdevice.h header file. To more accurately identify errors when you run the code analysis tools, be sure to add the _Use_decl_annotations_ annotation to your function definition. The _Use_decl_annotations_ annotation ensures that the annotations that are applied to the EVT_WDF_DEVICE_DISARM_WAKE_FROM_SX function type in the header file are used. For more information about the requirements for function declarations, see Declaring Functions by Using Function Role Types for KMDF Drivers. For information about _Use_decl_annotations_, see Annotating Function Behavior.

Requirements

Minimum KMDF version

1.0

Minimum UMDF version

2.0

Header

Wdfdevice.h (include Wdf.h)

IRQL

PASSIVE_LEVEL (see Remarks section)

See also

EvtDeviceArmWakeFromSx
EvtDeviceDisarmWakeFromS0
EvtDeviceWakeFromSxTriggered

 

 

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