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ACPI_THERMAL(4)	       FreeBSD Kernel Interfaces Manual	       ACPI_THERMAL(4)

     acpi_thermal -- ACPI thermal management subsystem

     device acpi

     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.

	     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.
	     If	set to 1, passive cooling is enabled.  It does cooling without
	     fans using	cpufreq(4) as the mechanism for	controlling CPU	speed.
	     Default is	enabled	for tz0	where it is available.
	     Current thermal zone status.  These are bit-masked	values.
	     Current temperature for this zone.
	     Temperature to start passive cooling by throttling	down CPU, etc.
	     Temperature to start critical suspend to disk (S4).
	     Temperature to start critical shutdown (S5).
	     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 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
		0xcc	Non-standard notify that the system will shutdown if
			the temperature	stays above _CRT or _HOT for one more
			poll cycle.

     acpi(4), cpufreq(4), acpidump(8)

     Michael Smith

     This manual page was written by Takanori Watanabe.

FreeBSD	10.2		       December	27, 2003		  FreeBSD 10.2


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