xref: /freebsd/share/man/man4/acpi_thermal.4 (revision 6b3455a7665208c366849f0b2b3bc916fb97516e)
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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 SYSCTLS
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.thermal_flags
64Current thermal zone status.
65These are bit-masked values.
66.It Va hw.acpi.thermal.tz%d.temperature
67Current temperature for this zone.
68.It Va hw.acpi.thermal.tz%d._PSV
69Temperature to start passive cooling by throttling down CPU, etc.
70.It Va hw.acpi.thermal.tz%d._HOT
71Temperature to start critical suspend to disk (S4).
72.It Va hw.acpi.thermal.tz%d._CRT
73Temperature to start critical shutdown (S5).
74.It Va hw.acpi.thermal.tz%d._ACx
75Temperatures at which to switch to the corresponding active cooling
76level.
77For instance, values of
78.Qq Li "3200 3100"
79mean to switch on _AC0 at 320.0K
80and _AC1 at 310.0K.
81The lower the _ACx value, the higher the cooling power.
82.El
83.Pp
84All temperatures are represented in tenths of a Kelvin.
85For example, 300.0K is represented by the integer 3000.
86To convert to units of Centigrade,
87the formula is
88.Li "(x - 2731.5) / 10" .
89.Sh NOTIFIES
90Notifies are passed to userland via
91.Xr devd 8 .
92See
93.Pa /etc/devd.conf
94and
95.Xr devd.conf 5
96for examples.
97The
98.Nm
99driver sends events with the following attributes:
100.Pp
101.Bl -tag -width "subsystem" -compact
102.It system
103.Li ACPI
104.It subsystem
105.Li Thermal
106.It type
107The fully qualified thermal zone object path as in the ASL.
108.It notify
109An integer designating the event:
110.Pp
111.Bl -tag -width indent -compact
112.It Li 0x80
113Current temperature has changed.
114.It Li 0x81
115One or more trip points (_ACx, _PSV) have changed.
116.It Li 0x82
117One or more device lists (_ALx, _PSL, _TZD) have changed.
118.It Li 0xcc
119Non-standard notify that the system will shutdown if the temperature
120stays above _CRT or _HOT for one more poll cycle.
121.El
122.El
123.Sh SEE ALSO
124.Xr acpi 4 ,
125.Xr acpidump 8
126.Sh AUTHORS
127.An -nosplit
128.An Michael Smith
129.Pp
130This manual page was written by
131.An Takanori Watanabe .
132