SetupDesignGuide.pdf - Firmware Encoding Index

Setup Design Guide
DRAFT
7.1.13 EFI_HII_PROTOCOL.GetKeyboardLayout()
Summary
This function allows a program to retrieve the keyboard layout data that has previously been registered
with the EFI HII database.
Prototype
EFI_STATUS
(EFIAPI *EFI_HII_GET_KEYBOARD_LAYOUT) (
IN EFI_HII_PROTOCOL *This,
IN OUT UINT16
DescriptorCount,
OUT EFI_KEY_DESCRIPTOR *Descriptor
);
Parameters
This
DescriptorCount
Descriptor
A pointer to the EFI_HII_PROTOCOL instance.
On input, the number of Descriptor entries the buffer can hold.
On output, the number of entries of the returned buffer, if the length
was sufficient and, if it was not, the number of entries that is required
to fit the requested keyboard layout data.
The pointer to the buffer designed to receive the keyboard layout
data.
Description
This function is used to extract the keyboard layout. The returned buffer will contain the current default
system descriptor data merged with any override keyboard data. For example, if the firmware default
keyboard is the U.S. keyboard and a driver added via NewPack a keyboard descriptor set for a
Germany keyboard, the layout which is retrieved will reflect the U.S. keyboard with the Germany
overrides.
If a program needed to acquire the base keyboard layout, it could do the following: Issue a
GetKeyboardLayout and cache the results. Issue a NewPack with a keyboard descriptor count of
zero to wipe out the keyboard overrides. Issue a GetKeyboardLayout to get the base keyboard
layout, and update via NewPack the original overrides.
Status Codes Returned
EFI_SUCCESS
EFI_BUFFER_TOO_SMALL
KeyDescriptor filled with the requested keyboard
layout. KeyDescriptorCount updated.
The buffer provided was not large enough to allow the
form to be stored.
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