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--- products:sbc:common:add-ons:cooling-fan [2022/11/16 20:38]
nick
+++ products:sbc:common:add-ons:cooling-fan [2026/02/02 01:44] (current)
gray update by using AI
@@ Line 3: / Line 3: @@
 ===== Introduction =====
-This page mainly introduces Cooling Fan. The first half describes how to control the Cooling Fan on Ubuntu, and the second half describes how to control the Cooling Fan on Android.
+This page introduces the [[https://www.khadas.com/product-page/3705-cooling-fan | Cooling Fan]]. The first section describes how to control the fan on Ubuntu, and the second section describes how to control it on Android.
 ===== Ubuntu =====
+<WRAP important>
+This setting is only applicable to 4.9, 5.15, 5.4, and 6.1 linux kernel
+</WRAP>
 ==== Fan Application ====
-The following method is recommended if you are using desktop OS. Find ''Fan Setting'' from the applications list. Open the app to control the cooling fan speed.
+This method is recommended if you are using a desktop OS. Find ''Fan Setting'' in the applications list. Open the app to control the cooling fan speed.
 {{/products/sbc/common/accessories/gnome_application_fan.png|gnome_application_fan}}
@@ Line 16: / Line 20: @@
 ==== Command Line ====
-You can also use command to control the FAN from terminal.
+You can also use commands to control the fan from the terminal.
-  * Set the fan mode: \\ ```shell
+=== Set the fan mode ===
-$ fan.sh off
-$ fan.sh on
+^ fan mode ^ command ^
-$ fan.sh auto
+| off | ''fan.sh off'' |
+| on | ''fan.sh on'' |
+| auto | ''fan.sh auto'' |
+=== Get the fan mode ===
+```shell
+fan.sh mode
 ```
-  * Read the fan mode: \\ ```shell
-$ fan.sh mode
+=== Set the fan speed ===
+^ fan speed ^ command ^
+| high | ''fan.sh high'' |
+| mid | ''fan.sh mid'' |
+| low | ''fan.sh low'' |
+=== Get CPU temperature ===
+```shell
+fan.sh temp
 ```
-  * Set the fan speed: \\ ```shell
-$ fan.sh high
+=== Get and Set the trigger temperature ===
-$ fan.sh mid
-$ fan.sh low
+You can read the trigger temperature from the following nodes:
+^ fan mode ^ trigger temp parameter ^
+| low | ''/sys/class/fan/trigger_temp_low'' |
+| mid | ''/sys/class/fan/trigger_temp_mid'' |
+| high | ''/sys/class/fan/trigger_temp_high'' |
+Example: Get the low trigger temperature:
+```shell
+cat /sys/class/fan/trigger_temp_low
 ```
-  * Read CPU temperature: \\ ```shell
+Example: Set the low trigger temperature to ''40'' Celsius.
-$ fan.sh temp
+```shell
+echo 40 | sudo tee /sys/class/fan/trigger_temp_low
 ```
+<WRAP tip >
+The trigger temperature only affects the fan when it is in auto mode.
+</WRAP>
+=== Mainline linux ===
+The fan is controlled automatically by the Linux thermal subsystem. Temperatures are in millidegrees Celsius.
+Example: Get the auto trigger temperature:
+```
+cat /sys/class/thermal/thermal_zone0/trip_point_3_temp
+```
+Example: set the auto trigger temp to 40000 millicelcius
+```
+echo 40000 | sudo tee /sys/class/thermal/thermal_zone0/trip_point_3_temp
+```
+<WRAP tip >
+To turn the fan off, set the trigger temperature to a higher value (e.g., 80000). \\
+To turn the fan on, set the trigger temperature to a lower value (e.g., 10000).
+</WRAP>
 ===== Android =====
-Just goto the system setting to control the FAN.
+Check system settings to control the fan.

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