Intel Extensible Firmware Interface - Manual (Page 461)

Protocols — PCI Bus Support
Version 1.10 12/01/02 12-43
Table 12-5 through Table 12-8 show example device paths for the PCI Root Bridges in a server
system with four PCI Root Bridges. Each of these device paths consists of an ACPI Device Path
Node, and a Device Path End Structure. The _HID and _UID must match the ACPI table
description of the PCI Root Bridges. The only difference between each of these device paths is the
_UID field. The shorthand notation for these four device paths is
ACPI(PNP0A03,0) ,
ACPI(PNP0A03,1) , ACPI(PNP0A03,2) , and ACPI(PNP0A03,3) .
Table 12-5. PCI Root Bridge Device Path for Bridge #0 in a Server System
Byte
Offset Byte
Length
Data
Description
0x00 0x01 0x02 Generic Device Path Header – Type ACPI Device Path
0x01 0x01 0x01 Sub type – ACPI Device Path
0x02 0x02 0x0C Length – 0x0C bytes
0x04 0x04 0x41D0,
0x0A03
_HID PNP0A03 – 0x41D0 represents a compressed string ‘PNP’ and is in
the low order bytes
0x08 0x04 0x0000 _UID
0x0C 0x01 0xFF Generic Device Path Header – Type End of Hardware Device Path
0x0D 0x01 0xFF Sub type – End of Entire Device Path
0x0E 0x02 0x04 Length – 0x04 bytes
Table 12-6. PCI Root Bridge Device Path for Bridge #1 in a Server System
Byte
Offset Byte
Length
Data
Description
0x00 0x01 0x02 Generic Device Path Header – Type ACPI Device Path
0x01 0x01 0x01 Sub type – ACPI Device Path
0x02 0x02 0x0C Length – 0x0C bytes
0x04 0x04 0x41D0,
0x0A03
_HID PNP0A03 – 0x41D0 represents a compressed string ‘PNP’ and is in
the low order bytes
0x08 0x04 0x0001 _UID
0x0C 0x01 0xFF Generic Device Path Header – Type End of Hardware Device Path
0x0D 0x01 0xFF Sub type – End of Entire Device Path
0x0E 0x02 0x04 Length – 0x04 bytes