---
name: "pchtherm"
section: "4"
platform: "freebsd"
package: "base"
version: "16.0-CURRENT-20261027-61c70dc16a79"
release: "FreeBSD 16.0-CURRENT (2026-10-27)"
platforms: ["freebsd"]
url: "https://new.carta.tech/pchtherm"
---

# pchtherm(4)

Intel PCH thermal subsystem

## NAME

**pchtherm** – Intel PCH thermal subsystem

## SYNOPSIS

**device pci** **device pchtherm**

## DESCRIPTION

The **pchtherm** driver provides access to sensor data and configuration installed in Intel PCH chipset. **pchtherm** configuration register.

The access to **pchtherm** data is made via the [sysctl(8)](/sysctl/8.md) 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:
```

- *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.

## CAVEATS

All values are read-only. And it do not support event interrupt for now.

## SEE ALSO

[sysctl(8)](/sysctl/8.md)

## HISTORY

The **pchtherm** driver first appeared in FreeBSD 13.0.

## AUTHORS

The **pchtherm** driver and this manual page were written by Takanori Watanabe ⟨*takawata@FreeBSD.org*⟩.