Advanced Configuration and Power Interface Specification

Advanced Configuration and Power Interface Specification
Return Value:
None
9.1.3 _BLT (Battery Level Threshold)
This optional control method is used by OSPM to indicate to the platform the user’s preference for
various battery level thresholds. This method allows platform battery indicators to be synchronized
with OSPM provided battery notification levels. Note that if _BLT is implemented on a multibattery
system, it is required that the power unit for all batteries must be the same. See Section 10.2
for more details on battery levels.
Arguments: (3)
Arg0 – An Integer containing the preferred threshold for the battery warning level
Arg1 – An Integer containing the preferred threshold for the battery low level
Arg2 – An Integer containing the preferred threshold for the battery wake level
Return Value:
None
Additional Information
The battery warning level in the range 0x00000001 – 0x7FFFFFFF (in units of mWh or mAh,
depending on the Power Units value) is the user’s preference for battery warning. If the level
specified is less than the design capacity of warning, it may be ignored by the platform so that the
platform can ensure a successful wake on low battery.
The battery low level in the range 0x00000001 – 0x7FFFFFFF (in units of mWh or mAh, depending
on the Power Units value) is the user’s preference for battery low. If this level is less than the design
capacity of low, it may be ignored by the platform.
The battery wake level in the range 0x00000001 – 0x7FFFFFFF (in units of mWh or mAh,
depending on the Power Units value) is the user’s preference for battery wake. If this level is less
than the platform’s current wake on low battery level, it may be ignored by the platform. If the
platform does not support a configurable wake on low battery level, this may be ignored by the
platform.
9.2 Ambient Light Sensor Device
The following section illustrates the operation and definition of the control method-based Ambient
Light Sensor (ALS) device.
The ambient light sensor device can optionally support power management objects (e.g. _PS0,
_PS3) to allow the OS to manage the device’s power consumption.
The Plug and Play ID of an ACPI control method ambient light sensor device is ACPI0008.
Table 9-255 Control Method Ambient Light Sensor Device
Object
_ALI
Description
The current ambient light illuminance reading in lux (lumen per square meter). [Required]
498 April, 2015 Version 6.0