xref: /freebsd-13-stable/share/man/man4/acpi_thermal.4 (revision b144e70a3325e033163aa4e6e15d0446e245702d)
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25.Dd March 17, 2007
26.Dt ACPI_THERMAL 4
27.Os
28.Sh NAME
29.Nm acpi_thermal
30.Nd ACPI thermal management subsystem
31.Sh SYNOPSIS
32.Cd "device acpi"
33.Sh DESCRIPTION
34The
35.Nm
36driver provides the thermal management features of the ACPI module.
37This driver has a
38.Xr sysctl 8
39interface and a
40.Xr devd 8
41notification interface.
42The sysctls export properties of each ACPI thermal zone object.
43.Pp
44There can be multiple thermal zones in a system.
45For example, each CPU and the enclosure could all be separate thermal
46zones, each with its own setpoints and cooling devices.
47Thermal zones are numbered sequentially in the order they appear in
48the AML.
49.Pp
50The
51.Nm
52driver also activates the active cooling system according to
53each thermal zone's setpoints.
54.Sh SYSCTL VARIABLES
55.Bl -tag -width indent
56.It Va hw.acpi.thermal.min_runtime
57Number of seconds to continue active cooling once started.
58A new active cooling level will not be selected until this interval expires.
59.It Va hw.acpi.thermal.polling_rate
60Number of seconds between polling the current temperature.
61.It Va hw.acpi.thermal.user_override
62If set to 1, allow user override of various setpoints (below).
63The original values for these settings are obtained from the BIOS and
64system overheating and possible damage could occur if changed.
65Default is 0 (no override).
66.It Va hw.acpi.thermal.tz%d.active
67Current active cooling system state.
68If this is non-negative, the appropriate _AC%d object is running.
69Set this value to the desired active cooling level to force
70the corresponding fan object to the appropriate level.
71.It Va hw.acpi.thermal.tz%d.passive_cooling
72If set to 1, passive cooling is enabled.
73It does cooling without fans using
74.Xr cpufreq 4
75as the mechanism for controlling CPU speed.
76Default is enabled for tz0 where it is available.
77.It Va hw.acpi.thermal.tz%d.thermal_flags
78Current thermal zone status.
79These are bit-masked values.
80.It Va hw.acpi.thermal.tz%d.temperature
81Current temperature for this zone.
82.It Va hw.acpi.thermal.tz%d._PSV
83Temperature to start passive cooling by throttling down CPU, etc.
84This value can be overridden by the user.
85.It Va hw.acpi.thermal.tz%d._HOT
86Temperature to start critical suspend to disk (S4).
87This value can be overridden by the user.
88.It Va hw.acpi.thermal.tz%d._CRT
89Temperature to start critical shutdown (S5).
90This value can be overridden by the user.
91.It Va hw.acpi.thermal.tz%d._ACx
92Temperatures at which to switch to the corresponding active cooling
93level.
94The lower the _ACx value, the higher the cooling power.
95.El
96.Pp
97All temperatures are printed in Celsius.
98Values can be set in Celsius (by providing a trailing
99.Qq C )
100or Kelvin (by leaving off any trailing letter).
101When setting a value by
102.Xr sysctl 8 ,
103do not specify a trailing decimal (i.e., 90C instead of 90.0C).
104.Sh NOTIFIES
105Notifies are passed to userland via
106.Xr devd 8 .
107See
108.Pa /etc/devd.conf
109and
110.Xr devd.conf 5
111for examples.
112The
113.Nm
114driver sends events with the following attributes:
115.Pp
116.Bl -tag -width "subsystem" -compact
117.It system
118.Li ACPI
119.It subsystem
120.Li Thermal
121.It type
122The fully qualified thermal zone object path as in the ASL.
123.It notify
124An integer designating the event:
125.Pp
126.Bl -tag -width indent -compact
127.It Li 0x80
128Current temperature has changed.
129.It Li 0x81
130One or more trip points (_ACx, _PSV) have changed.
131.It Li 0x82
132One or more device lists (_ALx, _PSL, _TZD) have changed.
133.It Li 0xcc
134Non-standard notify that the system will shutdown if the temperature
135stays above _CRT or _HOT for one more poll cycle.
136.El
137.El
138.Sh SEE ALSO
139.Xr acpi 4 ,
140.Xr cpufreq 4 ,
141.Xr acpidump 8
142.Sh AUTHORS
143.An -nosplit
144.An Michael Smith
145.Pp
146This manual page was written by
147.An Takanori Watanabe .
148