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EvtDeviceSelfManagedIoSuspend function

[Applies to KMDF and UMDF]

A driver's EvtDeviceSelfManagedIoSuspend event callback function suspends a device's self-managed I/O operations.

Syntax


EVT_WDF_DEVICE_SELF_MANAGED_IO_SUSPEND EvtDeviceSelfManagedIoSuspend;

NTSTATUS EvtDeviceSelfManagedIoSuspend(
  _In_  WDFDEVICE Device
)
{ ... }

Parameters

Device [in]

A handle to a framework device object.

Return value

If the operation is successful, the EvtDeviceSelfManagedIoSuspend callback function must return STATUS_SUCCESS, or another status value for which NT_SUCCESS(status) equals TRUE. Otherwise it must return a status value for which NT_SUCCESS(status) equals FALSE. If NT_SUCCESS(status) equals FALSE, the framework stops the device and removes its device objects.

If NT_SUCCESS(status) equals FALSE, the framework calls the driver's EvtDeviceSelfManagedIoFlush and EvtDeviceSelfManagedIoCleanup callback functions.

For more information about this callback function's return values, see Reporting Device Failures.

Remarks

To register an EvtDeviceSelfManagedIoSuspend callback function, a driver must call WdfDeviceInitSetPnpPowerEventCallbacks.

If the driver has registered an EvtDeviceSelfManagedIoSuspend callback function, the framework calls it for one of the following reasons:

  • The device is about to enter a low-power state.

  • The device is being removed or was surprise-removed.

  • The Plug and Play manager is about to redistribute the system's hardware resources among system's attached devices.

Because you do not know which of these events causes the framework to call your driver, you must assume that the device might return to its working (D0) state.

If the device is about to enter a low-power state, the framework calls the driver's EvtDeviceSelfManagedIoSuspend callback function before it calls the driver's EvtDeviceD0Exit callback function.

If the callback function returns a status value for which NT_SUCCESS(status) equals FALSE, and if the framework is attempting to lower the device's power, the framework stops the device and removes its device objects.

The EvtDeviceSelfManagedIoSuspend callback function must do whatever is needed to stop the device's self-managed I/O operations.

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

For more information about drivers that provide this callback function, see Using Self-Managed I/O.

Examples

To define an EvtDeviceSelfManagedIoSuspend 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 EvtDeviceSelfManagedIoSuspend callback function that is named MyDeviceSelfManagedIoSuspend, use the EVT_WDF_DEVICE_SELF_MANAGED_IO_SUSPEND type as shown in this code example:


EVT_WDF_DEVICE_SELF_MANAGED_IO_SUSPEND  MyDeviceSelfManagedIoSuspend;

Then, implement your callback function as follows:


_Use_decl_annotations_
NTSTATUS
 MyDeviceSelfManagedIoSuspend (
    WDFDEVICE  Device
    )
  {...}

The EVT_WDF_DEVICE_SELF_MANAGED_IO_SUSPEND 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_SELF_MANAGED_IO_SUSPEND 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 also

EvtDeviceSelfManagedIoCleanup
EvtDeviceSelfManagedIoFlush
EvtDeviceSelfManagedIoInit
EvtDeviceSelfManagedIoRestart

 

 

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