EvtDeviceDisarmWakeFromS0 function

[Applies to KMDF and UMDF]

A driver's EvtDeviceDisarmWakeFromS0 event callback function disarms (that is, disables) a device's ability to trigger a wake signal while in a low-power device state, if the system remains in the system working state (S0).

Syntax

C++


EVT_WDF_DEVICE_DISARM_WAKE_FROM_S0 EvtDeviceDisarmWakeFromS0;

VOID EvtDeviceDisarmWakeFromS0(
  _In_  WDFDEVICE Device
)
{ ... }

Parameters

Device [in]: A handle to a framework device object.

Return value

None

Remarks

To register an EvtDeviceDisarmWakeFromS0 callback function, a driver must call WdfDeviceInitSetPowerPolicyEventCallbacks. The driver must also set IdleCanWakeFromS0 in the IdleCaps member of its WDF_DEVICE_POWER_POLICY_IDLE_SETTINGS structure.

If the driver has registered an EvtDeviceDisarmWakeFromS0 callback function, the framework calls it after the bus driver determines that an event has awakened the device, and after the bus driver subsequently completes the wait/wake IRP. Before calling the driver's EvtDeviceDisarmWakeFromS0EvtDeviceDisarmWakeFromS0 callback function, the framework calls the driver's EvtDeviceD0Entry, EvtInterruptEnable, and EvtDeviceWakeFromS0Triggered callback functions.

The EvtDeviceDisarmWakeFromS0 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 Idle Power-Down.

The EvtDeviceDisarmWakeFromS0 callback function is called at IRQL = PASSIVE_LEVEL. You should not make this callback function pageable.

Examples

To define an EvtDeviceDisarmWakeFromS0 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 EvtDeviceDisarmWakeFromS0 callback function that is named MyDeviceDisarmWakeFromS0, use the EVT_WDF_DEVICE_DISARM_WAKE_FROM_S0 type as shown in this code example:


EVT_WDF_DEVICE_DISARM_WAKE_FROM_S0  MyDeviceDisarmWakeFromS0;

Then, implement your callback function as follows:


_Use_decl_annotations_
VOID
 MyDeviceDisarmWakeFromS0 (
    WDFDEVICE  Device
    )
  {...}

The EVT_WDF_DEVICE_DISARM_WAKE_FROM_S0 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_S0 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)