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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:

			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.

FreeBSD 5.4		       December 27, 2003		   FreeBSD 5.4

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