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ACPI_THERMAL (4) | Special files and drivers | Unix Manual Pages | :man

NAME

acpi_thermal - ACPI thermal management subsystem

CONTENTS

Synopsis
Description
Sysctl Variables
Notifies
See Also
Authors

SYNOPSIS


.Cd "device acpi"

DESCRIPTION

The acpi_thermal driver provides the thermal management features of the ACPI module. This driver has a sysctl(8) interface and a devd(8) notification interface. The sysctls export properties of each ACPI thermal zone object.

There can be multiple thermal zones in a system. For example, each CPU and the enclosure could all be separate thermal zones, each with its own setpoints and cooling devices. Thermal zones are numbered sequentially in the order they appear in the AML.

The acpi_thermal driver also activates the active cooling system according to each thermal zone’s setpoints.

SYSCTL VARIABLES

hw.acpi.thermal.tz%d.active
Current active cooling system state. If this is non-negative, the appropriate _AC%d object is running. Set this value to the desired active cooling level to force the corresponding fan object to the appropriate level.
hw.acpi.thermal.tz%d.thermal_flags
Current thermal zone status. These are bit-masked values.
hw.acpi.thermal.tz%d.temperature
Current temperature for this zone.
hw.acpi.thermal.tz%d._PSV
Temperature to start passive cooling by throttling down CPU, etc.
hw.acpi.thermal.tz%d._HOT
Temperature to start critical suspend to disk (S4).
hw.acpi.thermal.tz%d._CRT
Temperature to start critical shutdown (S5).
hw.acpi.thermal.tz%d._ACx
Temperatures at which to switch to the corresponding active cooling level. For instance, values of ""3200 3100"" mean to switch on _AC0 at 320.0K and _AC1 at 310.0K. The lower the _ACx value, the higher the cooling power.

All temperatures are represented in tenths of a Kelvin. For example, 300.0K is represented by the integer 3000. To convert to units of Centigrade, the formula is "(x - 2731.5) / 10".

NOTIFIES

Notifies are passed to userland via devd(8). See /etc/devd.conf and devd.conf(5) for examples. The acpi_thermal driver sends events with the following attributes:

system ACPI
subsystem Thermal
type The fully qualified thermal zone object path as in the ASL.
notify An integer designating the event:

0x80 Current temperature has changed.
0x81 One or more trip points (_ACx, _PSV) have changed.
0x82 One or more device lists (_ALx, _PSL, _TZD) have changed.
0xcc Non-standard notify that the system will shutdown if the temperature stays above _CRT or _HOT for one more poll cycle.

SEE ALSO

acpi(4), acpidump(8)

AUTHORS


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