11.5. Native OS Device Driver Thermal Interfaces

OS implementations compatible with the ACPI 3.0 thermal model, interface with the thermal objects of a thermal zone but also comprehend the thermal zone devices’ OS native device driver interfaces that perform similar functions to the thermal objects at the device level.

The recommended native OS device driver thermal interfaces that enable OSPM to perform optimal performance / thermal management include:

  • Reading a value from a device’s embedded thermal sensor

  • Reading a value that indicates whether temperature and trip point values are reported in absolute or relative temperatures

  • Setting the platform’s cooling mode policy setting

  • Reading the embedded thermal sensor’s threshold

  • Reading the device’s active and passive cooling temperature trip points

  • Reading the device’s association to a thermal zone

  • Signaling the crossing of a thermal trip point

  • Reading the desired polling frequency at which to check the devices temperature if the device cannot signal OSPM or signal OSPM optimally (both before and after a temperature trip point is crossed)

  • Setting / limiting a device’s performance / throttling states

  • Engaging / disengaging a device’s active cooling controls

These interfaces are OS specific and as such the OS vendor defines the exact interface definition for each target operating system.