EvtDriverDeviceAdd function

[Applies to KMDF and UMDF]

A driver's EvtDriverDeviceAdd event callback function performs device initialization operations when the Plug and Play (PnP) manager reports the existence of a device.

Syntax

C++


EVT_WDF_DRIVER_DEVICE_ADD EvtDriverDeviceAdd;

NTSTATUS EvtDriverDeviceAdd(
  _In_     WDFDRIVER Driver,
  _Inout_  PWDFDEVICE_INIT DeviceInit
)
{ ... }

Parameters

Driver [in]: A handle to a framework driver object that represents the driver.
DeviceInit [in, out]: A pointer to a framework-allocated WDFDEVICE_INIT structure.

Return value

TheEvtDriverDeviceAdd callback function must return STATUS_SUCCESS if the operation succeeds. Otherwise, this callback function must return one of the error status values that are defined in Ntstatus.h. For more information, see the following Remarks section.

Remarks

Each framework-based driver that supports PnP devices must provide the EvtDriverDeviceAdd callback function. The driver must place the callback function's address in its WDF_DRIVER_CONFIG structure before calling WdfDriverCreate.

The framework calls your driver's EvtDriverDeviceAdd callback function after a bus driver detects a device that has a hardware identifier (ID) that matches a hardware ID that your driver supports. You specify the hardware IDs that your driver supports by providing an INF file, which the operating system uses to install drivers the first time that one of your devices is connected to the computer. For more information about how the system uses INF files and hardware IDs, see How Setup Selects Drivers.

A driver's EvtDriverDeviceAdd callback function typically performs at least some of the following initialization operations:

Create a framework device object to represent the device.
Create I/O queues so the driver can receive I/O requests.
Create device interfaces that applications use to communicate with the device.
Create driver-defined interfaces that other drivers can use.
Initialize Windows Management Instrumentation (WMI) support.
Create interrupt objects, if the driver handles device interrupts.
Enable direct memory access (DMA) transactions, if the driver handles DMA operations.

Some drivers, especially filter drivers, might not create device objects for some devices. If an EvtDriverDeviceAdd callback function does not create a device object, it must still return STATUS_SUCCESS unless an error was encountered.

If a driver's EvtDriverDeviceAdd callback function creates a device object but does not return STATUS_SUCCESS, the framework deletes the device object and its child devices.

If a function driver's EvtDriverDeviceAdd callback function does not return STATUS_SUCCESS, the I/O manager does not build a device stack for the device.

If a filter driver's EvtDriverDeviceAdd callback function does not return STATUS_SUCCESS, the framework converts the return value to STATUS_SUCCESS, and the I/O manager builds the device stack without the filter driver.

Examples

To define an EvtDriverDeviceAdd 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 EvtDriverDeviceAdd callback function that is named MyDriverDeviceAdd, use the EVT_WDF_DRIVER_DEVICE_ADD type as shown in this code example:


EVT_WDF_DRIVER_DEVICE_ADD MyDriverDeviceAdd;

Then, implement your callback function as follows:


_Use_decl_annotations_
NTSTATUS 
 MyDriverDeviceAdd (
    WDFDRIVER Driver,
    PWDFDEVICE_INIT DeviceInit
    )
  {...}

The EVT_WDF_DRIVER_DEVICE_ADD function type is defined in the WdfDriver.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_DRIVER_DEVICE_ADD 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	Wdfdriver.h (include Wdf.h)
IRQL	PASSIVE_LEVEL