NAME
amdzentemp —
AMD Zen CPU family on-die
digital thermal sensor
SYNOPSIS
amdzentemp* at amdsmnbus?
DESCRIPTION
The
amdzentemp driver provides support for the on-die digital
thermal sensor present on AMD Ryzen CPUs
These sensors provide 0.125°C accuracy. There is one sensor for each CPU
socket.
The
amdzentemp driver reports temperatures through the
envsys(4) API.
Sensor |
Units |
Typical Use |
CPUN
sensor0 |
μK |
cpuN
temperature |
SEE ALSO
amdtemp(4),
envsys(4),
envstat(8),
powerd(8)
HISTORY
The
amdzentemp driver first appeared in
OpenBSD 4.4 named “kate”. It was then
ported to
NetBSD 5.0 under the name
amdtemp(4). The
FreeBSD version of the driver was updated with support
for newer AMD CPUs. For
NetBSD, the support for the
newer CPUs was separated into its own
amdzentemp driver.
AUTHORS
The
amdzentemp driver was written by
Constantine A. Murenin
<
cnst@openbsd.org>
whilst at the University of Waterloo. Porting of support for the newer AMD
CPUs from
FreeBSD was provided by
Ian
Clark.
BUGS
The temperature reading provided to
envsys(4) needs to have a
CPU-dependent offset applied. For Ryzen X processors, the offset is 20°C,
while for Threadripper processors an offset of 27°C is needed.
The sensor has a thermal-trip value which should be retrieved and provided to
envsys(4) as the sensors
critical-maximum value.