DXE driver refers to drivers compliant with the PI Specification, which classifies DXE drivers into two classes: UEFI driver model driver, and non-UEFI driver model drivers. The focus of this chapter is the non-UEFI drivers.
Non-UEFI Driver Model drivers are executed early in the DXE phase. These drivers are the prerequisites for the DXE Foundation to produce all required services.
The DXE drivers must be designed so that unavailable services are not required. Given this restriction, all possible work should be deferred to the UEFI drivers.