xref: /dragonfly/share/man/man4/acpi_thermal.4 (revision f02303f9)
1.\" Copyright (c) 2003 Takanori Watanabe.
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25.\" $FreeBSD: src/share/man/man4/acpi_thermal.4,v 1.6 2004/02/03 04:18:55 njl Exp $
26.\" $DragonFly: src/share/man/man4/acpi_thermal.4,v 1.2 2006/07/23 07:47:12 swildner Exp $
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28.Dd December 27, 2003
29.Dt ACPI_THERMAL 4
30.Os
31.Sh NAME
32.Nm acpi_thermal
33.Nd ACPI thermal management subsystem
34.Sh SYNOPSIS
35.Cd "device acpi"
36.Sh DESCRIPTION
37The
38.Nm
39driver provides the thermal management features of the ACPI module.
40This driver has a
41.Xr sysctl 8
42interface.
43The sysctls export properties of each ACPI thermal zone object.
44.Pp
45There can be multiple thermal zones in a system.
46For example, each CPU and the enclosure could all be separate thermal
47zones, each with its own setpoints and cooling devices.
48Thermal zones are numbered sequentially in the order they appear in
49the AML.
50.Pp
51The
52.Nm
53driver also activates the active cooling system according to
54each thermal zone's setpoints.
55.Sh SYSCTLS
56.Bl -tag -width indent
57.It Va hw.acpi.thermal.tz%d.active
58Current active cooling system state.
59If this is non-negative, the appropriate _AC%d object is running.
60Set this value to the desired active cooling level to force
61the corresponding fan object to the appropriate level.
62.It Va hw.acpi.thermal.tz%d.thermal_flags
63Current thermal zone status.
64These are bit-masked values.
65.It Va hw.acpi.thermal.tz%d.temperature
66Current temperature for this zone.
67.It Va hw.acpi.thermal.tz%d._PSV
68Temperature to start passive cooling by throttling down CPU, etc.
69.It Va hw.acpi.thermal.tz%d._HOT
70Temperature to start critical suspend to disk (S4).
71.It Va hw.acpi.thermal.tz%d._CRT
72Temperature to start critical shutdown (S5).
73.It Va hw.acpi.thermal.tz%d._ACx
74Temperatures at which to switch to the corresponding active cooling
75level.
76For instance, values of
77.Qq Li "3200 3100"
78mean to switch on _AC0 at 320.0K
79and _AC1 at 310.0K.
80The lower the _ACx value, the higher the cooling power.
81.El
82.Pp
83All temperatures are represented in tenths of a Kelvin.
84For example, 300.0K is represented by the integer 3000.
85To convert to units of Centigrade,
86the formula is
87.Li "(x - 2731.5) / 10" .
88.Sh SEE ALSO
89.Xr acpi 4 ,
90.Xr acpidump 8
91.Sh AUTHORS
92.An -nosplit
93.An Michael Smith
94.Pp
95This manual page was written by
96.An Takanori Watanabe .
97