Advanced Configuration and Power Interface Specification

ACPI-Defined Devices and Device-Specific Objects
9
ACPI-Defined Devices and Device-Specific
Objects
This section describes ACPI defined devices and device-specific objects. The system status indicator
objects, declared under the \_SI scope in the ACPI Namespace, are also specified in this section.
9.1 \_SI System Indicators
ACPI provides an interface for a variety of simple and icon-style indicators on a system. All
indicator controls are in the \_SI portion of the namespace. The following table lists all defined
system indicators. (Notice that there are also per-device indicators specified for battery devices).
Table 9-254 System Indicator Control Methods
Object
_SST
_MSG
_BLT
Description
System status indicator
Messages waiting indicator
Battery Level Threshold
9.1.1 _SST (System Status)
This optional object is a control method that OSPM invokes to set the system status indicator as
desired.
Arguments: (1)
Arg0 – An Integer containing the system status indicator identifier
0 – No system state indication. Indicator off
1 – Working
2 – Waking
3 – Sleeping. Used to indicate system state S1, S2, or S3
4 – Sleeping with context saved to non-volatile storage
Return Value:
None
9.1.2 _MSG (Message)
This control method sets the system’s message-waiting status indicator.
Arguments: (1)
Arg0 – An Integer containing the number of waiting messages
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