Advanced Configuration and Power Interface Specification

ACPI-Defined Devices and Device-Specific Objects
A generic bus bridge device is typically used for integrated bridges that have no other means of
controlling them and that have a set of well-known devices behind them. For example, a portable
computer can have a “generic bus bridge” known as an EIO bus that bridges to some number of
Super-I/O devices. The bridged resources are likely to be positively decoded as either a function of
the bridge or the integrated devices. In this example, a generic bus bridge device would be used to
declare the bridge then child devices would be declared below the bridge; representing the integrated
Super-I/O devices.
9.8 ATA Controller Devices
There are two types of ATA Controllers: IDE controllers (also known as ATA controllers) and Serial
ATA (SATA) controllers. IDE controllers are those using the traditional IDE programming
interface, and may support Parallel ATA (P-ATA) or SATA connections. SATA controllers may be
designed to operate in emulation mode only, native mode only, or they may be designed to support
both native and non-native SATA modes. Regardless of the mode supported, SATA controllers are
designed to work solely with drives supporting the Serial ATA physical interface. As described
below, SATA controllers are treated similarly but not identically to traditional IDE controllers.
Platforms that contain controllers that support native and non-native SATA modes must take steps to
ensure the proper objects are placed in the namespace for the mode in which they are operating.
Table 9-220 ATA Specific Objects
Object Description Controller
Type
_GTF Optional object that returns the ATA task file needed to re-initialize the drive to
boot up defaults.
Both
_GTM Optional object that returns the IDE controller timing information. IDE-only
_STM Optional control method that sets the IDE controller’s transfer timing settings. IDE-only
_SDD Optional control method that informs the platform of the type of device
attached to a port.
SATA-only
9.8.1 Objects for Both ATA and SATA Controllers
9.8.1.1 _GTF (Get Task File)
This optional object returns a buffer containing the ATA commands used to restore the drive to boot
up defaults (that is, the state of the drive after POST). The returned buffer is an array with each
element in the array consisting of seven 8-bit register values (56 bits) corresponding to ATA task
registers 1F1 thru 1F7. Each entry in the array defines a command to the drive.
Arguments:
None
Return Value:
A Buffer containing a byte stream of ATA commands for the drive
442 Hewlett-Packard/Intel/Microsoft/Phoenix/Toshiba