Intel Extensible Firmware Interface - Manual (Page 859)

Device Path Examples
Version 1.10 12/01/02 C-3
The EFI Device Path for the legacy floppy is defined in Table C-1. It would contain entries for the
following things:
• Root PCI Bridge. ACPI Device Path _HID PNP0A03, _UID 0. ACPI name space \_SB\PCI0
• PCI to ISA Bridge. PCI Device Path with device and function of the PCI to ISA bridge. ACPI
name space \_SB\PCI0\ISA0
• Floppy Plug and Play ID. ACPI Device Path _HID PNP0303, _UID 0. ACPI name space
\_SB\PCI0\ISA0\FLPY
• End Device Path
Table C-1. Legacy Floppy Device Path
Byte
Offset Byte
Length
Data
Description
0 1 0x02 Generic Device Path Header – Type ACPI Device Path
1 1 0x01 Sub type – ACPI Device Path
2 2 0x0C Length
4 4 0x41D0,
0x0A03
_HID PNP0A03 – 0x41D0 represents a compressed string ‘PNP’ and is in
the low order bytes
8 4 0x0000 _UID
C 1 0x01 Generic Device Path Header – Type Hardware Device Path
D 1 0x01 Sub type PCI Device Path
E 2 0x06 Length
10 1 0x00 PCI Function
11 1 0x10 PCI Device
12 1 0x02 Generic Device Path Header – Type ACPI Device Path
13 1 0x01 Sub type – ACPI Device Path
14 2 0x0C Length
16 4 0x41D0,
0x0303 _HID PNP0303
1A 4 0x0000 _UID
1E 1 0xFF Generic Device Path Header – Type End Device Path
1F 1 0xFF Sub type – End Device Path
20 2 0x04 Length
C.3 IDE Disk
The IDE Disk controller is a PCI device that is contained in a function of the root PCI host bridge.
The root PCI host bridge is a multi function device and has a separate function for chipset registers,
USB, and IDE. The disk connected to the IDE ATA bus is defined as being on the primary or
secondary ATA bus, and of being the master or slave device on that bus.