Intel Extensible Firmware Interface User Manual

Page 606

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Extensible Firmware Interface Specification

14-66 12/01/02

Version

1.10

Another example is a USB Controller (interface number 0) that is connected to port 3 of a USB
Hub Controller (interface number 0), and this USB Hub Controller is connected to the port 1 of the
root hub. The shorthand notation for this device path is:

ACPI(PNP0A03,0)/PCI(1F|2)/USB(1,0)/USB(3,0)

.

Table 14-5 shows the device path for this USB Controller.

Table 14-5. Another USB Device Path Example

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 0x01

Generic Device Path Header

– Type Hardware Device Path

0x0D

0x01 0x01 Sub

type

– PCI

0x0E

0x02 0x06 Length

– 0x06 bytes

0x10 0x01 0x1F PCI

Function

0x11

0x01 0x02 PCI

Device

0x12 0x01 0x03

Generic Device Path Header

– Type Message Device Path

0x13

0x01 0x05 Sub

type

– USB

0x14

0x02 0x06 Length

– 0x06 bytes

0x16

0x01

0x01

Parent Hub Port Number.

0x17

0x01 0x00 Controller

Interface

Number.

0x18 0x01 0x03

Generic Device Path Header

– Type Message Device Path

0x19

0x01 0x05 Sub

type

– USB

0x1A

0x02 0x06 Length

– 0x06 bytes

0x1C

0x01

0x03

Parent Hub Port Number.

0x1D

0x01 0x00 Controller

Interface

Number.

0x1E 0x01 0xFF

Generic Device Path Header

– Type End of Hardware Device Path

0x1F 0x01 0xFF Sub

type

– End of Entire Device Path

0x20

0x02 0x04 Length

– 0x04 bytes

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