xref: /freebsd/share/man/man4/acpi_thermal.4 (revision 2b15cb3d0922bd70ea592f0da9b4a5b167f4d53f)
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25.\" $FreeBSD$
26.\"
27.Dd March 17, 2007
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.
100Values can be set in Celsius (by providing a trailing
101.Qq C )
102or Kelvin (by leaving off any trailing letter).
103When setting a value by
104.Xr sysctl 8 ,
105do not specify a trailing decimal (i.e., 90C instead of 90.0C).
106.Sh NOTIFIES
107Notifies are passed to userland via
108.Xr devd 8 .
109See
110.Pa /etc/devd.conf
111and
112.Xr devd.conf 5
113for examples.
114The
115.Nm
116driver sends events with the following attributes:
117.Pp
118.Bl -tag -width "subsystem" -compact
119.It system
120.Li ACPI
121.It subsystem
122.Li Thermal
123.It type
124The fully qualified thermal zone object path as in the ASL.
125.It notify
126An integer designating the event:
127.Pp
128.Bl -tag -width indent -compact
129.It Li 0x80
130Current temperature has changed.
131.It Li 0x81
132One or more trip points (_ACx, _PSV) have changed.
133.It Li 0x82
134One or more device lists (_ALx, _PSL, _TZD) have changed.
135.It Li 0xcc
136Non-standard notify that the system will shutdown if the temperature
137stays above _CRT or _HOT for one more poll cycle.
138.El
139.El
140.Sh SEE ALSO
141.Xr acpi 4 ,
142.Xr cpufreq 4 ,
143.Xr acpidump 8
144.Sh AUTHORS
145.An -nosplit
146.An Michael Smith
147.Pp
148This manual page was written by
149.An Takanori Watanabe .
150