Intel Extensible Firmware Interface - Manual (Page 346)

Extensible Firmware Interface Specification
10-52 12/01/02 Version 1.10
Table 10-5. PS/2 Mouse Device Path (continued)
Byte
Offset Byte
Length
Data
Description
0x12 0x01 0x02 Generic Device Path Header – Type ACPI Device Path
0x13 0x01 0x01 Sub type – ACPI Device Path
0x14 0x02 0x0C Length – 0x0C bytes
0x16 0x04 0x41D0,
0x0F03
_HID PNP0F03 – 0x41D0 represents a compressed string ‘PNP’ and is in
the low order bytes.
0x1A 0x04 0x0000 _UID
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
Table 10-6 shows an example device path for a serial mouse that is located on COM 1 behind a PCI
to ISA bridge that is located at PCI device number 0x07 and PCI function 0x00. The PCI to ISA
bridge is directly attached to a PCI root bridge, and the communications parameters for COM 1 are
1200 baud, no parity, 8 data bits, and 1 stop bit. This device path consists of an ACPI Device Path
Node for the PCI Root Bridge, a PCI Device Path Node for the PCI to ISA bridge, an ACPI Device
Path Node for COM 1, a UART Device Path Node for the communications parameters, an ACPI
Device Path Node for the serial mouse, and a Device Path End Structure. The _HID and _UID of
the first ACPI Device Path Node must match the ACPI table description of the PCI Root Bridge.
The shorthand notation for this device path is:
ACPI(PNP0A03,0)/PCI(7|0)/ACPI(PNP0501,0)/UART(1200N81)/ACPI(PNP0F01,0)
Table 10-6. Serial Mouse Device Path
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
continued