FIC A360 Hardware Thermal Events, Active Cooling Strength, Software Functional Overview

Software Functional Overview

3.5.13 Hardware Thermal Events

An ACPI-compatible OS expects the hardware to generate a thermal event notification through the use of the SCI. When the OS receives the SCI event, it will run the _TMP control method to evaluate the current temperature. Then the OS will compare the value to the cooling policy temperatures. If the temperature has crossed over one of the three policy thresholds, then the OS will actively or passively cool (or stop cooling) the system, or shutdown the system entirely.

This is an SCI and you can define how ever many as necessary

90 _CRT

75 _AC0

60 _AC1

45 _PSV

5

Method

SCI Event

Figure 3-3 SCI Events

Both the number of SCI events to be implemented and the granularity of the temperature separation between each SCI event is OEM-specific. However, it is important to note that since the OS can use heuristic knowledge to help cool the system, the more events the OS receives the better understanding it will have of the system thermal characteristic.

3.5.14 Active Cooling Strength

The Active cooling methods (_Acx) in conjunction with active cooling lists (_ALx), allows an OEM to use a device that offers varying degrees of cooling capability or multiple cooling devices. The _ACx method designates the temperature at which the Active cooling is enabled or disabled (depending upon the direction in which the temperature is changing). The _ALx method evaluates to a list of devices that actively cool the zone. For example:

•If a standard single-speed fan is the Active cooling device, then the policy is represented by the temperature to which _AC0 evaluates, and the fan is listed in _AL0.

•If the zone uses two independently-controlled single-speed fans to regulate the temperature, then _AC0 will evaluate to the maximum cooling temperature using two fans, and _AC1 will evaluate to the standard cooling temperature using one fan.

•If a zone has a single fan with a low speed and a high speed, the _AC0 will evaluate to the temperature associated with running the fan at high-speed, and _AC1 will evaluate to the temperature associated with running the fan at low speed. _AL0 and _AL1 will both point to different device objects associated with the same physical fan, but control the fan at different speeds.

FIC A360 Service Manual 3-31