Intel Extensible Firmware Interface - Manual (Page 335)

Protocols — Console Support
Version 1.10 12/01/02 10-41
typedef struct _UGA_IO_REQUEST {
IN UGA_IO_REQUEST_CODE ioRequestCode;
IN PVOID pvInBuffer;
IN UINT64 ui64InBufferSize;
OUT PVOID pvOutBuffer;
IN UINT64 ui64OutBufferSize;
OUT UINT64 ui64BytesReturned;
} UGA_IO_REQUEST, *PUGA_IO_REQUEST;
A more complete definition of the data structures in this section can be found at
www.microsoft.com/hwdev/uga
Description
This is the main UGA service dispatch routine for all UGA_IO_REQUEST s. The
DispatchService() method exports all the support UGA_IO_REQUEST firmware
functionality of a device.
The EFI_UGA_DRAW_PROTCOL exist to provide lightweight access methods in the pre-OS space
to draw on the video screen. All the functionality of EFI_UGA_DRAW_PROTCOL can be accessed
directly via an IoRequest .
Status Codes Returned
The status returned by this function is defined on a per IoRequest basis.