EVT_WDF_IO_QUEUE_IO_RESUME callback function

[Applies to KMDF and UMDF]

A driver's EvtIoResume event callback function resumes processing a specified I/O request after the underlying device returns to its working (D0) power state.



VOID EvtIoResume(
  _In_ WDFQUEUE   Queue,
  _In_ WDFREQUEST Request
{ ... }


Queue [in]

A handle to the framework queue object that is associated with the I/O request.

Request [in]

A handle to a framework request object.

Return value



A driver registers an EvtIoResume callback function when it calls the WdfIoQueueCreate method. For more information about calling WdfIoQueueCreate, see Creating I/O Queues.

A driver registers EvtIoResume only for use with a power-managed queue.

The framework calls the driver's EvtIoResume callback function only if the driver's EvtIoStop callback function previously called WdfRequestStopAcknowledge with the Requeue parameter set to FALSE.

For more information about the EvtIoResume callback function, see Using Power-Managed I/O Queues.

This callback function can be called at IRQL <= DISPATCH_LEVEL, unless the ExecutionLevel member of the device or driver's WDF_OBJECT_ATTRIBUTES structure is set to WdfExecutionLevelPassive. You should not make this callback function pageable.


To define an EvtIoResume 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 EvtIoResume callback function that is named MyIoResume, use the EVT_WDF_IO_QUEUE_IO_RESUME type as shown in this code example:


Then, implement your callback function as follows:

 MyIoResume (
    WDFQUEUE  Queue,
    WDFREQUEST  Request

The EVT_WDF_IO_QUEUE_IO_RESUME function type is defined in the Wdfio.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_IO_QUEUE_IO_RESUME 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.


Target platform


Minimum KMDF version


Minimum UMDF version



Wdfio.h (include Wdf.h)


<= DISPATCH_LEVEL (see Remarks section)

See also




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