chapter2: recommend GOP

When the platform has graphics, recommend to implement the graphics output
protocol and warn that it will become mandatory in the future.

Make it clear that it does not comprise the EDID protocols or producing a
simple text output.

Signed-off-by: Vincent Stehlé <[email protected]>

Author: vstehle

source/chapter2-uefi.rst

@@ -116,6 +116,14 @@ All of the following UEFI elements are required for EBBR compliance.
    also sometimes called the `EFI_UNICODE_COLLATION2_PROTOCOL` or even the
    `EFI_UNICODE_COLLATION_PROTOCOL2`.
 
+When the platform has a graphical console device, it is recommended that
+firmware implements the `EFI_GRAPHICS_OUTPUT_PROTOCOL` as defined in
+:UEFI:`12.9`.
+
+.. warning:: A future version of this specification will make the
+   `EFI_GRAPHICS_OUTPUT_PROTOCOL` mandatory for platforms with a graphical
+   console device.
+
 The following table is a list of notable deviations from :UEFI:`2.6.2`.
 Many of these deviations are because the EBBR use cases do not require
 interface specific UEFI protocols, and so they have been made optional.
@@ -177,6 +185,9 @@ interface specific UEFI protocols, and so they have been made optional.
        the firmware itself rather than loaded as option ROMs.
        For this reason EBBR implementations are not required to support option
        ROM loading.
+   * - Graphics
+       Supporting `EFI_EDID_DISCOVERED_PROTOCOL` and `EFI_EDID_ACTIVE_PROTOCOL`,
+       and producing `EFI_SIMPLE_TEXT_OUTPUT_PROTOCOL` is not required.
 
 .. _section-required-global-vars: