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Extensible Firmware Interface Specification
10-42 12/01/02 Version 1.10
10.8 Implementation Rules for an EFI UGA Driver
An EFI driver designed to manage the UGA controller must follow the EFI 1.10 driver model and
thus produce an EFI_DRIVER_BINDING_PROTOCOL
and follow the rules on implementing the
Supported()
, Start(), and Stop(). The Start() function must not initialize or start the
video hardware, and it should just register an EFI_UGA_IO_PROTOCOL
and one or more
EFI_UGA_DRAW_PROTOCOL
(s). The video hardware must be initialized via
EFI_UGA_IO_PROTOCOL I/O requests or via the first call to
EFI_UGA_DRAW_PROTOCOL.SetMode()
.
An EFI_UGA_DRAW_PROTOCOL must be implemented for every video frame buffer that exists
on a video adapter. In most cases there will be a single EFI_UGA_DRAW_PROTOCOL placed on
the Controller handle passed into the EFI_DRIVER_BINDING.Start() function. As a UGA
ROM can contain more than one EFI Image, the EFI_UGA_DRAW_PROTOCOL can be produced
by a separate driver that consumes the EFI_UGA_IO_PROTOCOL.
An EFI_UGA_IO_PROTOCOL must be produced on the Controller handle passed into the
EFI_DRIVER_BINDING.Start() function. There is only one EFI_UGA_IO_PROTOCOL
produced for every device being managed by an UGA ROM.
For PCI based video device all hardware access will be done via EFI_UGA_IO_PROTOCOL. This
includes IO, MMIO, BAR based access, and DMA.
The EFI Boot Service and Runtime APIs are used to allocate memory and register protocol
interfaces.
Every UGA device must support an 800 x 600 x 32-bit color per pixel at 60 Hz by video mode.
The EFI_UGA_IO_PROTOCOL.UgaIoDispatchServce()
function must support the
following UGA_IO_REQUESTs:
UgaIoCopyRectangle
UgaIoFlushDevice
UgaIoGetChildDevice
UgaIoGetDeviceProperty
UgaIoGetDevicePropertySize
UgaIoGetDeviceState
UgaIoGetMemoryConfiguration
UgaIoResetDevice
UgaIoSetDeviceState
UgaIoSetPowerState
UgaIoSetVideoMode
UgaIoStartDevice
UgaIoStopDevice