Device Handle To Protocol Handler Mapping - Intel Extensible Firmware Interface Specification

Extensible Firmware Interface Specification
First Handle
The ability to add new protocol interfaces as new handles or to layer them on existing interfaces
provides great flexibility. Layering makes it possible to add a new protocol that builds on a
device's basic protocols. An example of this might be to layer on a
protocol support that would build on the handle's underlying
The ability to add new handles can be used to generate new devices as they are found, or even to
generate abstract devices. An example of this might be to add a multiplexing device that replaces
with a virtual device that multiplexes the
ConsoleOut
multiple underlying device handles.
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Device Handle
GUID
Interface
Protocol
Interface
Instance
Data
Device Handle
GUID
Interface
Protocol
Interface
Instance
Data
...
Figure 3-1. Device Handle to Protocol Handler Mapping
12/12/00
GUID GUID
Interface Interface
Protocol Protocol
Interface Interface
Instance Instance
Data Data
GUID
Interface
Protocol
Interface
Instance
Data
SIMPLE_TEXT_OUTPUT
SERIAL_IO
SIMPLE_TEXT_OUTPUT
GUID
Interface
Protocol
Interface
Instance
Data
protocol.
protocol onto
Version 1.02