Intel Extensible Firmware Interface - Manual (Page 422)

Extensible Firmware Interface Specification
12-4 12/01/02 Version 1.10
12.1.1.1 Sample PCI Architectures
The PCI Root Bridge I/O Protocol is designed to provide a software abstraction for a wide variety
of PCI architectures including the ones described in this section. This section is not intended to be
an exhaustive list of the PCI architectures that the PCI Root Bridge I/O Protocol can support.
Instead, it is intended to show the flexibility of this protocol to adapt to current and future platform
designs.
Figure 12-3 shows an example of a PCI Host Bus with one PCI Root Bridge. This PCI Root Bridge
produces one PCI Local Bus that can contain PCI Devices on the motherboard and/or PCI slots.
This would be typical of a desktop system. A higher end desktop system might contain a second
PCI Root Bridge for AGP devices. The firmware for this platform would produce one instance of
the PCI Root Bridge I/O Protocol.
OM13161
PCI Local Bus
Core Chipset Components
PCI Host Bus
PCI Root Bridge
Figure 12-3. Desktop System with One PCI Root Bridge