1.\" $NetBSD: amdzentemp.4,v 1.7 2020/04/20 11:09:48 simonb Exp $ 2.\"- 3.\" Copyright (c) 2008 Christoph Egger 4.\" All rights reserved. 5.\" 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 9.\" 1. Redistributions of source code must retain the above copyright 10.\" notice, this list of conditions and the following disclaimer. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice, this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 15.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 16.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 17.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 18.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 19.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 20.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 21.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 22.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 23.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 25.\" SUCH DAMAGE. 26.\" 27.\" $FreeBSD: src/share/man/man4/coretemp.4,v 1.4 2007/10/15 20:00:19 netchild Exp $ 28.\" 29.Dd April 20, 2020 30.Dt AMDZENTEMP 4 x86 31.Os 32.Sh NAME 33.Nm amdzentemp 34.Nd AMD Zen CPU family on-die digital thermal sensor 35.Sh SYNOPSIS 36.Cd "amdzentemp* at amdsmnbus?" 37.Sh DESCRIPTION 38The 39.Nm 40driver provides support for the on-die digital thermal sensor present 41on AMD Ryzen CPUs and some later AMD Opteron CPUs. 42.Pp 43These sensors provide 0.125\(deC accuracy. 44There is one sensor for each CPU socket. 45.Pp 46The 47.Nm 48driver reports temperatures through the 49.Xr envsys 4 50API. 51.Bl -column "CPUN sensor0" "Units" "Typical Use" -offset indent 52.It Sy "Sensor" Ta Sy "Units" Ta Sy "Typical Use" 53.It CPU Ns Em N No sensor0 Ta \(*mK Ta cpu Ns Em N No temperature 54.El 55.Sh SEE ALSO 56.Xr amdtemp 4 , 57.Xr envsys 4 , 58.Xr envstat 8 , 59.Xr powerd 8 60.Sh HISTORY 61The 62.Nm 63driver first appeared in 64.Ox 4.4 65named 66.Dq kate . 67It was then ported to 68.Nx 5.0 69under the name 70.Xr amdtemp 4 . 71The 72.Fx 73version of the driver was updated with support for newer AMD CPUs. 74For 75.Nx , 76the support for the newer CPUs was separated into its own 77.Nm 78driver. 79.Sh AUTHORS 80.An -nosplit 81The 82.Nm 83driver was written by 84.An Constantine A. Murenin Aq Mt cnst@openbsd.org 85whilst at the University of Waterloo. 86Porting of support for the newer AMD CPUs from 87.Fx 88was provided by 89.An Ian Clark . 90.Sh BUGS 91The temperature reading provided to 92.Xr envsys 4 93needs to have a CPU-dependent offset applied. 94For Ryzen X processors, the offset is 20\(deC, while for Threadripper 95processors an offset of 27\(deC is needed. 96.Pp 97The sensor has a thermal-trip value which should be retrieved and 98provided to 99.Xr envsys 4 100as the sensors critical-maximum value. 101