Intel Extensible Firmware Interface - Manual (Page 330)

Extensible Firmware Interface Specification
10-36 12/01/02 Version 1.10
The EFI_UGA_IO_PROTOCOL operates on UGA_DEVICE objects. Child devices can be
enumerated by using DispatchService() to send a pIoRequest of type
UgaIoGetChildDevice . A UGA_DEVICE object can be created via a call to
CreateDevice() with the data returned from UgaIoGetChildDevice .
A video device can support an arbitrary number of geometries, but it must support one of the
following modes to operate with the
EFI_UGA_IO_PROTOCOL :
• 800 x 600 with 32-bit color with a 60 Hz refresh rate.
The advanced features of a UGA device are accessible via its
DispatchService() . More
information on the advanced capabilities of an EFI 1.10 UGA ROM can be found at
www.microsoft.com/hwdev/uga .