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ACPI_THERMAL(4)          BSD Kernel Interfaces Manual          ACPI_THERMAL(4)

NAME
     acpi_thermal -- ACPI thermal management subsystem

SYNOPSIS
     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) notifi-
     cation 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 accord-
     ing to each thermal zone's setpoints.

SYSCTLS
     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 cool-
             ing 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 Centi-
     grade, 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
     Michael Smith

     This manual page was written by Takanori Watanabe.

BSD                            December 27, 2003                           BSD