Advanced Configuration and Power Interface Specification

ACPI-Defined Devices and Device-Specific Objects
Emulation mode
Native mode
Hybrid Device
Optional mode supported by a SATA HBA. Allows non-native
SATA aware software to access SATA devices via traditional
task file registers.
Optional mode supported by a SATA HBA. Allows native SATA
aware software to access SATA devices via registers that are
specific to the HBA.
Refers to a SATA HBA that implements both an emulation and a
native programming interface.
9.8.3.2 Overview
A SATA HBA differs from an IDE controller in a number of ways. First, it can save its complete
device context. Second, it replaces IDE channels, which may support up to 2 attached devices, with
ports, which support only a single attached device, unless a port multiplier is present. See the SATA
spec at “Links to ACPI-Related Documents” (http://uefi.org/acpi) under the heading "SATA
Specification"for more information. Finally, SATA does not require timing information from the
platform, allowing a simplification in how SATA controllers are represented in ACPI. (_GTM and
_STM are replaced by the simpler _SDD method.)
All ports, even those attached off a port multiplier, are represented as children directly under the
SATA controller device. This is practical because the SATA specification does not allow a port
multiplier to be attached to a port multiplier. Each port’s _ADR indicates to which root port they are
connected, as well as the port multiplier location, if applicable. (See Table 6-168 for _ADR format.)
Since this specification only covers the configuration of motherboard devices, it is also the case that
the control methods defined in this section cannot be used to send taskfiles to devices attached via
either an add-in SATA HBA, or attached via a motherboard SATA HBA, if used with a port
multiplier that is not also on the motherboard.
The following shows an example SATA namespace:
\_SB
- System bus
PCI0
- PCI bus
SATA - SATA Controller device
ADR
- Indicates address of the controller on the PCI bus
PR0
- Power resources needed for D0 power state
PRT0 - Port 0 device
_ADR - Indicates physical port and port multiplier topology
_SDD - Identify information for drive attached to this port
_GTF - Control method to get task file
PRTn - Port n device
_ADR - Indicates physical port and port multiplier topology
_SDD - Identify information for drive attached to this port
_GTF - Control method to get task file
9.8.3.3 SATA controller-specific control methods
In order to ensure proper interaction between OSPM, the firmware, and devices attached to the
SATA controller, it is a requirement that OSPM execute the _SDD and _GTF control methods when
certain events occur. OSPM’s response to events must be as follows:
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