Intel Extensible Firmware Interface - Manual (Page 140)

Extensible Firmware Interface Specification
5-42 12/01/02 Version 1.10
RegisterProtocolNotify()
Summary
Creates an event that is to be signaled whenever an interface is installed for a specified protocol.
Prototype
EFI_STATUS
RegisterProtocolNotify (
IN EFI_GUID *Protocol,
IN EFI_EVENT Event,
OUT VOID **Registration
);
Parameters
Protocol The numeric ID of the protocol for which the event is to be registered.
Type
EFI_GUID is defined in the
InstallProtocolInterface() function description.
Event Event that is to be signaled whenever a protocol interface is registered
for
Protocol . The type EFI_EVENT is defined in the
InstallProtocolInterface() function description. The same
EFI_EVENT may be used for multiple protocol notify registrations.
Registration A pointer to a memory location to receive the registration value. This
value must be saved and used by the notification function of
Event to
retrieve the list of handles that have added a protocol interface of type
Protocol .
Description
The RegisterProtocolNotify() function creates an event that is to be signaled whenever a
protocol interface is installed for Protocol by InstallProtocolInterface() or
ReinstallProtocolInterface() .
Once Event has been signaled, the LocateHandle() function can be called to identify the
newly installed, or reinstalled, handles that support Protocol . The Registration parameter
in RegisterProtocolNotify() corresponds to the SearchKey parameter in
LocateHandle() . Note that the same handle may be returned multiple times if the handle
reinstalls the target protocol ID multiple times. This is typical for removable media devices,
because when such a device reappears, it will reinstall the Block I/O protocol to indicate that the
device needs to be checked again. In response, layered Disk I/O and Simple File System protocols
may then reinstall their protocols to indicate that they can be re-checked, and so forth.
Status Codes Returned
EFI_SUCCESS The notification event has been registered.
EFI_OUT_OF_RESOURCES Space for the notification event could not be allocated.
EFI_INVALID_PARAMETER One of the parameters has an invalid value.