Kontron COMe-bCD2 - Manual (Page 43)

8 Important Technology Information
Kontron User's Guide ETXexpress® CD 43
8.4 Thermal Management
ACPI allows the OS to play a role in the thermal management of the system. With the OS in control of the
operating environment, cooling decisions can be made based on the application load on the CPU and the
thermal heuristics of the system.
The ACPI thermal solution on COMe-bCD2 supports three cooling policies:
Active Cooling
The OS is turning the fan on/off. Active cooling devices typically consume power and produce noise, but
are able to cool a thermal zone without limiting system performance. The active cooling trip point
declares the temperature threshold the OS uses to decide when to start/stop active cooling devices.
Passive Cooling
The OS reduces the power consumption of the processor by throttling the processor clock to reduce the
temperature of the thermal zone. Passive cooling devices (processor) produce no noise. The passive
cooling trip point declares the temperature threshold where the OS will start or stop passive cooling.
Critical Trip Point
The OS performs an orderly, but critical, shutdown of the system when the temperature reaches the
critical trip point.