acpi_thermal —
ACPI thermal management subsystem
device acpi
The
acpi_thermal driver provides the thermal
management features of the ACPI module. This driver has a
sysctl(8) interface and a
devd(8) notification interface. The sysctls
export properties of each ACPI thermal zone object.
There can be multiple thermal zones in a system. For example, each CPU and the
enclosure could all be separate thermal zones, each with its own setpoints and
cooling devices. Thermal zones are numbered sequentially in the order they
appear in the AML.
The
acpi_thermal driver also activates the active
cooling system according to each thermal zone's setpoints.
- hw.acpi.thermal.min_runtime
- Number of seconds to continue active cooling once started.
A new active cooling level will not be selected until this interval
expires.
- hw.acpi.thermal.polling_rate
- Number of seconds between polling the current
temperature.
- hw.acpi.thermal.user_override
- If set to 1, allow user override of various setpoints
(below). The original values for these settings are obtained from the BIOS
and system overheating and possible damage could occur if changed. Default
is 0 (no override).
- hw.acpi.thermal.tz%d.active
- Current active cooling system state. If this is
non-negative, the appropriate _AC%d object is running. Set this value to
the desired active cooling level to force the corresponding fan object to
the appropriate level.
- hw.acpi.thermal.tz%d.passive_cooling
- If set to 1, passive cooling is enabled. It does cooling
without fans using cpufreq(4) as the
mechanism for controlling CPU speed. Default is enabled for tz0 where it
is available.
- hw.acpi.thermal.tz%d.thermal_flags
- Current thermal zone status. These are bit-masked
values.
- hw.acpi.thermal.tz%d.temperature
- Current temperature for this zone.
- hw.acpi.thermal.tz%d._PSV
- Temperature to start passive cooling by throttling down
CPU, etc. This value can be overridden by the user.
- hw.acpi.thermal.tz%d._HOT
- Temperature to start critical suspend to disk (S4). This
value can be overridden by the user.
- hw.acpi.thermal.tz%d._CRT
- Temperature to start critical shutdown (S5). This value can
be overridden by the user.
- hw.acpi.thermal.tz%d._ACx
- Temperatures at which to switch to the corresponding active
cooling level. The lower the _ACx value, the higher the cooling
power.
All temperatures are printed in Celsius. Values can be set in Celsius (by
providing a trailing “C”) or Kelvin (by leaving off any trailing
letter). When setting a value by
sysctl(8), do
not specify a trailing decimal (i.e., 90C instead of 90.0C).
Notifies are passed to userland via
devd(8). See
/etc/devd.conf and
devd.conf(5) for examples. The
acpi_thermal driver sends events with the
following attributes:
- system
ACPI- subsystem
Thermal- type
- The fully qualified thermal zone object path as in the
ASL.
- notify
- An integer designating the event:
0x80- Current temperature has changed.
0x81- One or more trip points (_ACx, _PSV) have changed.
0x82- One or more device lists (_ALx, _PSL, _TZD) have
changed.
0xcc- Non-standard notify that the system will shutdown if
the temperature stays above _CRT or _HOT for one more poll cycle.
acpi(4),
cpufreq(4),
acpidump(8)
Michael Smith
This manual page was written by
Takanori
Watanabe.