Description¶

This driver permits reading of the internal temperature sensor of AMDFamily 10h/11h/12h/14h/15h/16h processors.

All these processors have a sensor, but on those for Socket F or AM2+,the sensor may return inconsistent values (erratum 319). The driverwill refuse to load on these revisions unless you specify the “force=1”module parameter.

Due to technical reasons, the driver can detect only the mainboard’ssocket type, not the processor’s actual capabilities. Therefore, if youare using an AM3 processor on an AM2+ mainboard, you can safely use the“force=1” parameter.

For CPUs older than Family 17h, there is one temperature measurement value,available as temp1_input in sysfs. It is measured in degrees Celsius with aresolution of 1/8th degree. Please note that it is defined as a relativevalue; to quote the AMD manual:

Tctl is the processor temperature control value, used by the platform tocontrol cooling systems. Tctl is a non-physical temperature on anarbitrary scale measured in degrees. It does _not_ represent an actualphysical temperature like die or case temperature. Instead, it specifiesthe processor temperature relative to the point at which the system mustsupply the maximum cooling for the processor's specified maximum casetemperature and maximum thermal power dissipation.

The maximum value for Tctl is available in the file temp1_max.

If the BIOS has enabled hardware temperature control, the threshold atwhich the processor will throttle itself to avoid damage is available intemp1_crit and temp1_crit_hyst.

On some AMD CPUs, there is a difference between the die temperature (Tdie) andthe reported temperature (Tctl). Tdie is the real measured temperature, andTctl is used for fan control. While Tctl is always available as temp1_input,the driver exports Tdie temperature as temp2_input for those CPUs which supportit.

Models from 17h family report relative temperature, the driver aims tocompensate and report the real temperature.

On Family 17h and Family 18h CPUs, additional temperature sensors may reportCore Complex Die (CCD) temperatures. Up to 8 such temperatures are reportedas temp{3..10}_input, labeled Tccd{1..8}. Actual support depends on the CPUvariant.

Various Family 17h and 18h CPUs report voltage and current telemetryinformation. The following attributes may be reported.

Attribute Label Description=============== ======= ================in0_input Vcore Core voltagein1_input Vsoc SoC voltagecurr1_input Icore Core currentcurr2_input Isoc SoC current=============== ======= ================

Current values are raw (unscaled) as reported by the CPU. Core current isreported as multiples of 1A / LSB. SoC is reported as multiples of 0.25A/ LSB. The real current is board specific. Reported currents should be seenas rough guidance, and should be scaled using sensors3.conf as appropriatefor a given board.