_WDF_STATE_NOTIFICATION_TYPE enumeration

Description

[Applies to KMDF only]

[!NOTE] This enumeration is for Microsoft internal use only.

The WDF_STATE_NOTIFICATION_TYPE enumeration identifies the type of Plug and Play, power, or power policy notification that a framework-based driver will receive.

Constants

StateNotificationInvalid:0x0000

For internal use only.

StateNotificationEnterState:0x0001

The driver is notified immediately before a device's Plug and Play, power, or power policy state machine enters a specified state.

StateNotificationPostProcessState:0x0002

The driver is notified immediately after a device's Plug and Play, power, or power policy state machine enters a specified state.

StateNotificationLeaveState:0x0004

The driver is notified immediately before a device's Plug and Play, power, or power policy state machine leaves a specified state.

StateNotificationAllStates:StateNotificationEnterState | StateNotificationPostProcessState | StateNotificationLeaveState

The driver receives enter-state, postprocess-state, and leave-state notifications.

Remarks

When the framework's state machine for a driver's device changes from state a to state b, the framework notifies the driver (if the driver registered an appropriate event callback function), in the following sequence:

1. Calls state a's leave-state notification callback function.
2. Calls state b's enter-state notification callback function.
3. Changes the device's state from a to b.
4. Calls state b's postprocess-state notification callback function.

To register for notification of a change in state, the driver can call the following methods:

• WdfDeviceInitRegisterPnpStateChangeCallback
• WdfDeviceInitRegisterPowerStateChangeCallback
• WdfDeviceInitRegisterPowerPolicyStateChangeCallback

See also

WDF_DEVICE_PNP_NOTIFICATION_DATA

WDF_DEVICE_POWER_NOTIFICATION_DATA

WDF_DEVICE_POWER_POLICY_NOTIFICATION_DATA