Emulating legacy video using UEFI

摘要

Techniques for supporting legacy VGA video using UEFI standard and extended UEFI graphics drivers. When an operating system that does not natively support the UEFI display protocols requires video services provided by firmware, the operating system communicates a request for video services to a generic video option ROM. The generic video option ROM notifies a generic video SMM driver of the request for video services. Such notification may be performed using a software system management interrupt (SMI). Upon notification, the generic video SMM driver notifies a third party UEFI video driver of the request for video services. The third party video driver provides the requested video services to the operating system. In this way, a third party UEFI graphics driver may support a wide variety of operating systems, even those that do not natively support the UEFI display protocols.