pchtherm(4)

📦 version 15.1, in freebsd 14.5, freebsd 15.1, nixpkgs unstable

🎀 NAME 🎀

Bestie, this is pchtherm(4) — the Intel PCH thermal subsystem. That's the name, that's the vibe, and we're about to read every single sysctl knob together like it's the group chat. 💅

✨ SYNOPSIS ✨

device pci
device pchtherm

💖 DESCRIPTION 💖

The pchtherm driver provides access to sensor data and configuration installed in Intel PCH chipset. Also: pchtherm configuration register. Not me being obsessed with a register sentence, but here we are.

The access to pchtherm data is made via the sysctl(8) interface:

dev.pchtherm.0.ctt: 115.0C
dev.pchtherm.0.temperature: 28.5C
dev.pchtherm.0.t2temp: 91.0C
dev.pchtherm.0.t1temp: 86.0C
dev.pchtherm.0.t0temp: 81.0C
dev.pchtherm.0.tahv: 83.0C
dev.pchtherm.0.talv: 30.0C
dev.pchtherm.0.pmtime: 32
dev.pchtherm.0.pmtemp: 50.0C
dev.pchtherm.0.%parent: pci0
dev.pchtherm.0.%pnpinfo: vendor=0x8086 device=0x9d31 subvendor=0x17aa subdevice=0x2256 class=0x118000
dev.pchtherm.0.%location: slot=20 function=2 dbsf=pci0:0:20:2
dev.pchtherm.0.%driver: pchtherm
dev.pchtherm.0.%desc: Skylake PCH Thermal Subsystem
dev.pchtherm.%parent:

The dev.pchtherm.%d.* knobs are lowkey the whole plot:

  • dev.pchtherm.%d.temperature — Is the read-only value of the current temperature read by the sensor.
  • dev.pchtherm.%d.ctt — When the system reaches this temperature, it will shut down. This will not appear when this feature is disabled and locked down.
  • dev.pchtherm.%d.t0temp — When temperature is under this value, system will be in T0 state.
  • dev.pchtherm.%d.t1temp — When temperature is over t0temp and under this value, system will be in T1 state.
  • dev.pchtherm.%d.t2temp — When temperature is over t1temp and under this value, system will be in T2 state. Over this value, system will be in T3 state.
  • dev.pchtherm.%d.talv — Lower alart value. This will not appear when sensor enable bit is locked down and the value is zero(which will show -50.0C).
  • dev.pchtherm.%d.tahv — High alart value. This will not appear when sensor enable bit is locked down and the value is zero(which will show -50.0C).
  • dev.pchtherm.%d.pmtemp — Sensor Power management temperature. Under this temperature, sensor will idle during pmtime second.
  • dev.pchtherm.%d.pmtime — Sensor idle duration when low temperature.
  • dev.pchtherm.%d.pch_hot_level — When temperature is higher than this value, PCHHOT# pin will assert. This value is not appear when this feature is disabled and locked down.

Please check the PCH datasheets for more details. iykyk, datasheets are the real main characters.

💀 CAVEATS 💀

All values are read-only. And it do not support event interrupt for now. That's the whole caveat, bestie — no event interrupt energy yet.

👀 SEE ALSO 👀

sysctl(8) — go check it out, that's the one.

🌈 HISTORY 🌈

The pchtherm driver first appeared in FreeBSD 13.0. Periodt.

👑 AUTHORS 👑

The pchtherm driver and this manual page were written by Takanori Watanabe <takawata@FreeBSD.org>. We stan a documented driver.

xoxo, your Debian bestie — March 15, 2020 — pchtherm(4) 💖✨

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