xref: /freebsd/share/man/man4/acpi_thermal.4 (revision 963e8efffe4ab97233102e0e25f95061b6fefbe3)
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25.\" $FreeBSD$
26.\"
27.Dd July 29, 2006
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.min_runtime
59Number of seconds to continue active cooling once started.
60A new active cooling level will not be selected until this interval expires.
61.It Va hw.acpi.thermal.polling_rate
62Number of seconds between polling the current temperature.
63.It Va hw.acpi.thermal.user_override
64If set to 1, allow user override of various setpoints (below).
65The original values for these settings are obtained from the BIOS and
66system overheating and possible damage could occur if changed.
67Default is 0 (no override).
68.It Va hw.acpi.thermal.tz%d.active
69Current active cooling system state.
70If this is non-negative, the appropriate _AC%d object is running.
71Set this value to the desired active cooling level to force
72the corresponding fan object to the appropriate level.
73.It Va hw.acpi.thermal.tz%d.passive_cooling
74If set to 1, passive cooling is enabled.
75It does cooling without fans using
76.Xr cpufreq 4
77as the mechanism for controlling CPU speed.
78Default is enabled for tz0 where it is available.
79.It Va hw.acpi.thermal.tz%d.thermal_flags
80Current thermal zone status.
81These are bit-masked values.
82.It Va hw.acpi.thermal.tz%d.temperature
83Current temperature for this zone.
84.It Va hw.acpi.thermal.tz%d._PSV
85Temperature to start passive cooling by throttling down CPU, etc.
86This value can be overridden by the user.
87.It Va hw.acpi.thermal.tz%d._HOT
88Temperature to start critical suspend to disk (S4).
89This value can be overridden by the user.
90.It Va hw.acpi.thermal.tz%d._CRT
91Temperature to start critical shutdown (S5).
92This value can be overridden by the user.
93.It Va hw.acpi.thermal.tz%d._ACx
94Temperatures at which to switch to the corresponding active cooling
95level.
96The lower the _ACx value, the higher the cooling power.
97.El
98.Pp
99All temperatures are printed in Celsius.
100When setting a value by
101.Xr sysctl 8 ,
102do not specify a trailing decimal (i.e., 90 instead of 90.0C).
103.Sh NOTIFIES
104Notifies are passed to userland via
105.Xr devd 8 .
106See
107.Pa /etc/devd.conf
108and
109.Xr devd.conf 5
110for examples.
111The
112.Nm
113driver sends events with the following attributes:
114.Pp
115.Bl -tag -width "subsystem" -compact
116.It system
117.Li ACPI
118.It subsystem
119.Li Thermal
120.It type
121The fully qualified thermal zone object path as in the ASL.
122.It notify
123An integer designating the event:
124.Pp
125.Bl -tag -width indent -compact
126.It Li 0x80
127Current temperature has changed.
128.It Li 0x81
129One or more trip points (_ACx, _PSV) have changed.
130.It Li 0x82
131One or more device lists (_ALx, _PSL, _TZD) have changed.
132.It Li 0xcc
133Non-standard notify that the system will shutdown if the temperature
134stays above _CRT or _HOT for one more poll cycle.
135.El
136.El
137.Sh SEE ALSO
138.Xr acpi 4 ,
139.Xr cpufreq 4 ,
140.Xr acpidump 8
141.Sh AUTHORS
142.An -nosplit
143.An Michael Smith
144.Pp
145This manual page was written by
146.An Takanori Watanabe .
147