| SMNTEMP(4D) | Devices | SMNTEMP(4D) |
smntemp — AMD SMN
Temperature Sensor Driver
/dev/sensors/temperature/cpu/*
The smntemp driver provides the system
access to the temperature and control sensors found in the AMD System
Management Network (SMN) on Zen 1-5 processors (AMD Family 17h, 19h, and
1ah).
Each CCD, core complex die, present in the SoC exposes its own temperature in degrees Celsius. This covers the temperature of the CCD as a whole and could be thought of as a temperature sensor for all the cores and caches in the die. There is no per-core temperature sensor available.
In addition, a control temperature is exposed for each I/O die, Zen 2 and newer, or each Zeppelin die, Zen 1. The control temperature is a unitless measure derived from the temperature that indicates to cooling infrastructure what action to take and can take any value on the range 0 to 100. A value of 95 indicates that thermal throttling should be occurring and a value of 100 indicates that the chip will hit its thermal limit and shut down if no action is taken. Critically, the control temperature is not truly a measure of degrees!
Temperature information is available to the system
via the fault management architecture (FMA). The file system location and
programming interface to the smntemp driver are
considered
Volatile,
subject to change without notice, and should not be used directly. Raw
temperature information can be dumped through the FMA developer utility
fmtopo.
amdnbtemp(4D), amdzen(4D), fmadm(8)
AMD, Open-Source Register Reference For AMD Family 17h Processors Models 00h-2Fh, July, 2018.
| May 22, 2024 | OmniOS |