thermal-conf.xml(5) File Formats Manual thermal-conf.xml(5)
NAME
thermal-conf.xml - Configuration file for thermal daemon
SYNOPSIS
$(TDCONFDIR)/etc/thermald/thermal-conf.xml
DESCRIPTION
thermal-conf.xml is a configuration file for the thermal daemon. It is
used to configure thermal sensors, zone and cooling devices.The loca-
tion of this file depends on the configuration option used during build
time.
The terminology used in this file conforms to "Advanced Configuration
and Power Interface Specification". The ACPI thermal model is based
around conceptual platform regions called thermal zones that physically
contain devices, thermal sensors, and cooling controls. For example of
a thermal zone can be a CPU or a laptop cover. A zone can contain mul-
tiple sensors for monitoring temperature. A cooling device provides in-
terface to reduce the temperature of a source device, which causes in-
crease in the temperature. An example of a cooling device is a FAN or
some Linux driver which can throttle the source device.
A thermal zone configuration includes one or more trip points. A trip
point is a temperature at which a cooling device needs to be activated.
A cooling device can be either active or passive. An example of an ac-
tive device is a FAN, which will not reduce performance at the cost of
consuming more power and noise. A passive device uses performance
throttling to control temperature. In addition to cooling devices
present in the thermal sysfs, the following cooling devices are built
into the thermald, which can be used as valid cooling device type:
- rapl_controller
- intel_pstate
- cpufreq
- LCD
The thermal sysfs under Linux (/sys/class/thermal) provides a way to
represent per platform ACPI configuration. The kernel thermal governor
uses this data to keep the platform thermals under control. But there
are some limitations, which thermald tries to resolve. For example:
- If the ACPI data is not optimized or buggy. In this case thermal-
conf.xml can be used to correct the behavior without change in BIOS.
- There may be thermal zones exposed by the thermal sysfs with-
out associated cooling actions. In this case thermal conf.xml
can be used to tie the cooling devices to those zones.
- The best cooling method may not be in the thermal sysfs. In
this case thermal-conf.xml can be used to bind a zone to an ex-
ternal cooling device.
- Specify thermal relationships. A zone can be influenced by
multiple source devices with varying degrees. In this case ther-
mal-conf.xml can be used to define the relative influence for
apply compensation.
FILE FORMAT
The configuration file format conforms to XML specifications. A set of
tags defined to define platform, sensors, zones, cooling devices and
trip points.
<ThermalConfiguration>
<Platform>
<Name>Example Platform Name</Name>
<!-- UUID is optional, if present this will be matched. Both product
name and UUID can contain wild card "*", which matches any
platform. -->
<UUID>Example UUID</UUID>
<!-- configuration file format conforms to XML specifications. A
set of tags defined to define platform, sensors, zones, cooling
devices and trip points. -->
<ProductName>Example Product Name</ProductName>
<Preference>QUIET|PERFORMANCE</Preference>
<!-- Quiet mode will only use passive cooling device. "PERFORMANCE"
will only select active devices. -->
<ThermalSensors>
<ThermalSensor>
<!-- New Sensor with a type and path -->
<Type>example_sensor_1</Type>
<Path>/some_path</Path>
<AsyncCapable>0</AsyncCapable>
</ThermalSensor>
<ThermalSensor>
<!-- Already present in thermal sysfs, enable this or
add/change config For example, here we are indicating
that sensor can do async events to avoid polling. -->
<Type>example_thermal_sysfs_sensor</Type>
<!-- If async capable, then we don't need to poll. -->
<AsyncCapable>1</AsyncCapable>
</ThermalSensor>
</ThermalSensors>
<ThermalZones>
<ThermalZone>
<Type>Example Zone type</Type>
<TripPoints>
<TripPoint>
<SensorType>example_sensor_1</SensorType>
<!-- Temperature at which to take action. -->
<Temperature> 75000 </Temperature>
<!-- max/passive/active If a MAX type is specified, then
daemon will use PID control to aggressively throttle
to avoid reaching this temp. -->
<type>max</type>
<!-- SEQUENTIAL | PARALLEL. When a trip point temp is
violated, then number of cooling devices can be
activated. If control type is SEQUENTIAL then, it
will exhaust first cooling device
before trying next. -->
<ControlType>SEQUENTIAL</ControlType>
<CoolingDevice>
<index>1</index>
<type>example_cooling_device</type>
<!-- Influence will be used order cooling devices. First
cooling device will be used, which has highest
influence. -->
<influence> 100 </influence>
<!-- Delay in using this cdev, this takes some time too
actually cool a zone. -->
<SamplingPeriod> 12 </SamplingPeriod>
<!-- Set a specific state of this cooling device when this
trip is violated. -->
<TargetState> 6 </TargetState>
</CoolingDevice>
</TripPoint>
</TripPoints>
</ThermalZone>
</ThermalZones>
<CoolingDevices>
<CoolingDevice>
<!-- Cooling device can be specified by a type and optionally
a sysfs path. If the type is already present in thermal
sysfs, there is no need of a path. Compensation can use
min/max and step size to increasing cool the system.
Debounce period can be used to force a waiting period
for action. -->
<Type>example_cooling_device</Type>
<MinState>0</MinState>
<IncDecStep>10</IncDecStep>
<ReadBack> 0 </ReadBack>
<MaxState>50</MaxState>
<DebouncePeriod>5000</DebouncePeriod>
<!-- If there are no PID parameters, compensation increase step
wise and exponentially (if single step is not able to
change trend).
Alternatively a PID parameters can be specified then next
step will use PID calculation using provided PID
constants. -->
<PidControl>
<kp>0.001</kp>
<kd>0.0001</kd>
<ki>0.0001</ki>
</PidControl>
<!-- Write some prefix attached to state value, like below the
prefix is "level ". It will preserve spaces as entered
when writing to sysfs. -->
<WritePrefix>level </WritePrefix>
</CoolingDevice>
</CoolingDevices>
</Platform>
</ThermalConfiguration>
EXAMPLE CONFIGURATIONS
Example 1: This is a very simple configuration, to change the passive
limit on the CPU. Instead of default, this new temperature 86C in the
configuration is used. This will start cooling, once the temperature
reaches 86C.
<?xml version="1.0"?>
<ThermalConfiguration>
<Platform>
<Name>Override CPU default passive</Name>
<ProductName>*</ProductName>
<Preference>QUIET</Preference>
<ThermalZones>
<ThermalZone>
<Type>cpu</Type>
<TripPoints>
<TripPoint>
<Temperature>86000</Temperature>
<type>passive</type>
</TripPoint>
</TripPoints>
</ThermalZone>
</ThermalZones>
</Platform>
</ThermalConfiguration>
Example 2: In this configuration, we are controlling backlight when
some sensor "SEN2" reaches 60C. Here "LCD" is a standard cooling de-
vice, which uses Linux backlight sysfs interface. "LCD_Zone" is a valid
thermal zone in Linux thermal sysfs on the test platform, hence we
don't need to provide path for sysfs for "LCD_Zone". The Linux thermal
sysfs is already parsed and loaded by thermald program.
<?xml version="1.0"?>
<ThermalConfiguration>
<Platform>
<Name>Change Backlight</Name>
<ProductName>*</ProductName>
<Preference>QUIET</Preference>
<ThermalZones>
<ThermalZone>
<Type>LCD_Zone</Type>
<TripPoints>
<TripPoint>
<SensorType>SEN2</SensorType>
<Temperature>60000</Temperature>
<type>passive</type>
<CoolingDevice>
<Type>LCD</Type>
</CoolingDevice>
</TripPoint>
</TripPoints>
</ThermalZone>
</ThermalZones>
</Platform>
</ThermalConfiguration>
Example 3: In this example Lenovo Thinkpad X220 and fan speed is con-
trolled. Here a cooling device "_Fan", can be controlled via sysfs
/sys/devices/platform/thinkpad_hwmon/pwm1. When the x86_pkg_temp
reaches 45C, Fan is started with increasing speeds, if the temperature
can't be controlled at 45C.
<?xml version="1.0"?>
<ThermalConfiguration>
<Platform>
<Name>Lenovo ThinkPad X220</Name>
<ProductName>*</ProductName>
<Preference>QUIET</Preference>
<ThermalZones>
<ThermalZone>
<Type>x86_pkg_temp</Type>
<TripPoints>
<TripPoint>
<SensorType>x86_pkg_temp</SensorType>
<Temperature>45000</Temperature>
<type>passive</type>
<ControlType>SEQUENTIAL</ControlType>
<CoolingDevice>
<index>1</index>
<type>_Fan</type>
<influence> 100 </influence>
<SamplingPeriod> 12 </SamplingPeriod>
</CoolingDevice>
</TripPoint>
</TripPoints>
</ThermalZone>
</ThermalZones>
<CoolingDevices>
<CoolingDevice>
<Type>_Fan</Type>
<Path>/sys/devices/platform/thinkpad_hwmon/pwm1</Path>
<MinState>0</MinState>
<IncDecStep>30</IncDecStep>
<ReadBack> 0 </ReadBack>
<MaxState>255</MaxState>
<DebouncePeriod>5</DebouncePeriod>
</CoolingDevice>
</CoolingDevices>
</Platform>
</ThermalConfiguration>
Example 4: The following example shows how PID can be used. Here once
temperature exceeds 80C, compensation is calculated using PID using 80C
as set point of PID. The compensation depends on error from the set
point. Here the default built in processor cooling device is used with
min state as 0 and max state as 10.
<?xml version="1.0"?>
<ThermalConfiguration>
<Platform>
<Name>Use PID param </Name>
<ProductName>*</ProductName>
<Preference>QUIET</Preference>
<ThermalZones>
<ThermalZone>
<Type>x86_pkg_temp</Type>
<TripPoints>
<TripPoint>
<SensorType>x86_pkg_temp</SensorType>
<Temperature>80000</Temperature>
<type>passive</type>
<ControlType>SEQUENTIAL</ControlType>
<CoolingDevice>
<type>Processor</type>
</CoolingDevice>
</TripPoint>
</TripPoints>
</ThermalZone>
</ThermalZones>
<CoolingDevices>
<CoolingDevice>
<Type>Processor</Type>
<PidControl>
<kp>0.0002</kp>
<kd>0</kd>
<ki>0</ki>
</PidControl>
</CoolingDevice>
</CoolingDevices>
</Platform>
</ThermalConfiguration>
Example 5: The following example shows how to control Fan when the
sysfs expects some string prefix. For example instead of just write a
number to fan control sysfs, the interface requires "level " in front
of the speed index value.
<?xml version="1.0"?>
<ThermalConfiguration>
<Platform>
<Name>Use Fan control first then CPU throttle </Name>
<ProductName>*</ProductName>
<Preference>QUIET</Preference>
<ThermalZones>
<ThermalZone>
<Type>x86_pkg_temp</Type>
<TripPoints>
<TripPoint>
<SensorType>x86_pkg_temp</SensorType>
<Temperature>80000</Temperature>
<type>passive</type>
<ControlType>SEQUENTIAL</ControlType>
<CoolingDevice>
<type>_fan_</type>
</CoolingDevice>
</TripPoint>
</TripPoints>
</ThermalZone>
</ThermalZones>
<CoolingDevices>
<CoolingDevice>
<Type>_fan_</Type>
<Path>/proc/acpi/ibm/fan</Path>
<WritePrefix>level </WritePrefix>
<MinState>0</MinState>
<MaxState>5</MaxState>
<DebouncePeriod>10</DebouncePeriod>
</CoolingDevice>
</CoolingDevices>
</Platform>
</ThermalConfiguration>
Example 6: Similar to example 5, but write different speeds at differ-
ent temperatures.
<?xml version="1.0"?>
<ThermalConfiguration>
<Platform>
<Name>Use Fan control first then CPU throttle </Name>
<ProductName>*</ProductName>
<Preference>QUIET</Preference>
<ThermalZones>
<ThermalZone>
<Type>x86_pkg_temp</Type>
<TripPoints>
<TripPoint>
<SensorType>x86_pkg_temp</SensorType>
<Temperature>80000</Temperature>
<type>passive</type>
<CoolingDevice>
<type>_fan_</type>
<TargetState>1</TargetState>
</CoolingDevice>
</TripPoint>
<TripPoint>
<SensorType>x86_pkg_temp</SensorType>
<Temperature>85000</Temperature>
<type>passive</type>
<CoolingDevice>
<type>_fan_</type>
<TargetState>2</TargetState>
</CoolingDevice>
</TripPoint>
</TripPoints>
</ThermalZone>
</ThermalZones>
<CoolingDevices>
<CoolingDevice>
<Type>_fan_</Type>
<Path>/proc/acpi/ibm/fan</Path>
<WritePrefix>level </WritePrefix>
<MinState>0</MinState>
<MaxState>5</MaxState>
<DebouncePeriod>10</DebouncePeriod>
</CoolingDevice>
</CoolingDevices>
</Platform>
</ThermalConfiguration>
18 Dec 2018 thermal-conf.xml(5)
Generated by dwww version 1.14 on Mon Feb 3 08:25:48 CET 2025.