The LDI enables kernel device consumers to register for event notification and to receive event notification from target devices. A kernel device consumer can register an event handler that will be called when the event occurs. The kernel device consumer must open a device and receive a layered driver handle before the kernel device consumer can register for event notification with the LDI event notification interfaces.
The LDI event notification interfaces enable a kernel device consumer to specify an event name and to retrieve an associated kernel event cookie. The kernel device consumer can then pass the layered driver handle (ldi_handle_t), the cookie (ddi_eventcookie_t), and the event handler to ldi_add_event_handler(9F) to register for event notification. When registration completes successfully, the kernel device consumer receives a unique LDI event handler identifier (ldi_callback_id_t). The LDI event handler identifier is an opaque type that can be used only with the LDI event notification interfaces.
The LDI provides a framework to register for events generated by other devices. The LDI itself does not define any event types or provide interfaces for generating events.
The following describes the LDI asynchronous event notification interfaces:
Event handler identifier. An opaque type.
Retrieve an event service cookie for the target device specified by the layered driver handle.
Add the callback handler specified by the ldi_callback_id_t registration identifier. The callback handler is invoked when the event specified by the ddi_eventcookie_t cookie occurs.
Remove the callback handler specified by the ldi_callback_id_t registration identifier.