Description¶

This driver permits reading the DTS (Digital Temperature Sensor) embeddedinside Intel CPUs. This driver can read both the per-core and per-packagetemperature using the appropriate sensors. The per-package sensor is new;as of now, it is present only in the SandyBridge platform. The driver willshow the temperature of all cores inside a package under a single devicedirectory inside hwmon.

Temperature is measured in degrees Celsius and measurement resolution is1 degree C. Valid temperatures are from 0 to TjMax degrees C, becausethe actual value of temperature register is in fact a delta from TjMax.

Temperature known as TjMax is the maximum junction temperature of processor,which depends on the CPU model. See table below. At this temperature, protectionmechanism will perform actions to forcibly cool down the processor. Alarmmay be raised, if the temperature grows enough (more than TjMax) to triggerthe Out-Of-Spec bit. Following table summarizes the exported sysfs files:

All Sysfs entries are named with their core_id (represented here by ‘X’).

On CPU models which support it, TjMax is read from a model-specific register.On other models, it is set to an arbitrary value based on weak heuristics.If these heuristics don’t work for you, you can pass the correct TjMax valueas a module parameter (tjmax).

Appendix A. Known TjMax lists (TBD):Some information comes from ark.intel.com