6 UEFI Driver Categories

The different categories of UEFI drivers are introduced in Chapter 3 of this guide. These driver categories are discussed throughout this document, but emphasis is placed on drivers that follow the UEFI driver model because they are the most commonly implemented. The driver categories that follow the UEFI driver model include:

• Device drivers

• Bus drivers

• Hybrid drivers

There are several subtypes and optional features for the three categories of drivers. This chapter introduces the subtypes and optional features of drivers that follow the UEFI driver model. Understanding the different categories of UEFI drivers helps driver writers identify the category of driver to implement and the algorithms used in their implementation. The less common service drivers, root bridge drivers and initializing drivers are also discussed. Appendix B contains a table of example drivers from the EDK II along with the features that each implement.