Advanced Configuration and Power Interface Specification

Advanced Configuration and Power Interface Specification
must identify which device on the enumerable bus is identified by a particular address; the ACPI
system firmware must supply an _ADR object for each device to enable this. A device object must
contain either an _HID object or an _ADR object, but should not contain both.
If any of these objects are implemented as control methods, these methods may depend on operation
regions. Since the control methods may be evaluated before an operation region provider becomes
available, the control method must be structured to execute in the absence of the operation region
provider. (_REG methods notify the BIOS of the presence of operation region providers.) When a
control method cannot determine the current state of the hardware due to a lack of operation region
provider, it is recommended that the control method should return the condition that was true at the
time that control passed from the BIOS to the OS. (The control method should return a default, boot
value).
6.1.1 _ADR (Address)
This object is used to supply OSPM with the address of a device on its parent bus. An _ADR object
must be used when specifying the address of any device on a bus that has a standard enumeration
algorithm (see Section 3.7, “Configuration and Plug and Play”, for the situations when these devices
do appear in the ACPI namespace).
Arguments:
None
Return Value:
An Integer containing the address of the device
An _ADR object can be used to provide capabilities to the specified address even if a device is not
present. This allows the system to provide capabilities to a slot on the parent bus.
OSPM infers the parent bus and segment from the location of the _ADR object’s device package in
the ACPI namespace. For more information about the positioning of device packages in the ACPI
namespace, see Section 19.6.30, “Device (Declare Bus/Device Package)”
_ADR object information must be static and can be defined for the following bus types listed in
Table 6-168.
Table 6-168 ADR Object Address Encodings
BUS
Address Encoding
EISA EISA slot number 0–F
Floppy Bus Drive select values used for programming the floppy controller to access the specified
INT13 unit number. The _ADR Objects should be sorted based on drive select encoding
from 0-3.
IDE Controller 0–Primary Channel, 1–Secondary Channel
IDE Channel 0–Master drive, 1–Slave drive
Intel® High
Definition Audio
PCI
High word – SDI (Serial Data In) ID of the codec that contains the function group.
Low word – Node ID of the function group.
High word–Device #, Low word–Function #. (for example, device 3, function 2 is
0x00030002). To refer to all the functions on a device #, use a function number of FFFF).
278 April, 2015 Version 6.0