xref: /freebsd/share/man/man4/acpi_thermal.4 (revision 87569f75a91f298c52a71823c04d41cf53c88889)
1.\" Copyright (c) 2003 Takanori Watanabe.
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25.\" $FreeBSD$
26.\"
27.Dd December 27, 2003
28.Dt ACPI_THERMAL 4
29.Os
30.Sh NAME
31.Nm acpi_thermal
32.Nd ACPI thermal management subsystem
33.Sh SYNOPSIS
34.Cd "device acpi"
35.Sh DESCRIPTION
36The
37.Nm
38driver provides the thermal management features of the ACPI module.
39This driver has a
40.Xr sysctl 8
41interface and a
42.Xr devd 8
43notification interface.
44The sysctls export properties of each ACPI thermal zone object.
45.Pp
46There can be multiple thermal zones in a system.
47For example, each CPU and the enclosure could all be separate thermal
48zones, each with its own setpoints and cooling devices.
49Thermal zones are numbered sequentially in the order they appear in
50the AML.
51.Pp
52The
53.Nm
54driver also activates the active cooling system according to
55each thermal zone's setpoints.
56.Sh SYSCTL VARIABLES
57.Bl -tag -width indent
58.It Va hw.acpi.thermal.tz%d.active
59Current active cooling system state.
60If this is non-negative, the appropriate _AC%d object is running.
61Set this value to the desired active cooling level to force
62the corresponding fan object to the appropriate level.
63.It Va hw.acpi.thermal.tz%d.passive_cooling
64If set to 1, passive cooling is enabled.
65It does cooling without fans using
66.Xr cpufreq 4
67as the mechanism for controlling CPU speed.
68Default is enabled for tz0 where it is available.
69.It Va hw.acpi.thermal.tz%d.thermal_flags
70Current thermal zone status.
71These are bit-masked values.
72.It Va hw.acpi.thermal.tz%d.temperature
73Current temperature for this zone.
74.It Va hw.acpi.thermal.tz%d._PSV
75Temperature to start passive cooling by throttling down CPU, etc.
76.It Va hw.acpi.thermal.tz%d._HOT
77Temperature to start critical suspend to disk (S4).
78.It Va hw.acpi.thermal.tz%d._CRT
79Temperature to start critical shutdown (S5).
80.It Va hw.acpi.thermal.tz%d._ACx
81Temperatures at which to switch to the corresponding active cooling
82level.
83For instance, values of
84.Qq Li "3200 3100"
85mean to switch on _AC0 at 320.0K
86and _AC1 at 310.0K.
87The lower the _ACx value, the higher the cooling power.
88.El
89.Pp
90All temperatures are represented in tenths of a Kelvin.
91For example, 300.0K is represented by the integer 3000.
92To convert to units of Centigrade,
93the formula is
94.Li "(x - 2731.5) / 10" .
95.Sh NOTIFIES
96Notifies are passed to userland via
97.Xr devd 8 .
98See
99.Pa /etc/devd.conf
100and
101.Xr devd.conf 5
102for examples.
103The
104.Nm
105driver sends events with the following attributes:
106.Pp
107.Bl -tag -width "subsystem" -compact
108.It system
109.Li ACPI
110.It subsystem
111.Li Thermal
112.It type
113The fully qualified thermal zone object path as in the ASL.
114.It notify
115An integer designating the event:
116.Pp
117.Bl -tag -width indent -compact
118.It Li 0x80
119Current temperature has changed.
120.It Li 0x81
121One or more trip points (_ACx, _PSV) have changed.
122.It Li 0x82
123One or more device lists (_ALx, _PSL, _TZD) have changed.
124.It Li 0xcc
125Non-standard notify that the system will shutdown if the temperature
126stays above _CRT or _HOT for one more poll cycle.
127.El
128.El
129.Sh SEE ALSO
130.Xr acpi 4 ,
131.Xr cpufreq 4 ,
132.Xr acpidump 8
133.Sh AUTHORS
134.An -nosplit
135.An Michael Smith
136.Pp
137This manual page was written by
138.An Takanori Watanabe .
139