https://github.com/markusressel/fan2go
A simple daemon providing dynamic fan speed control based on temperature sensors.
https://github.com/markusressel/fan2go
daemon fan fan-speed fancontrol golang hacktoberfest pwm rpm temperature
Last synced: 12 days ago
JSON representation
A simple daemon providing dynamic fan speed control based on temperature sensors.
- Host: GitHub
- URL: https://github.com/markusressel/fan2go
- Owner: markusressel
- License: agpl-3.0
- Created: 2021-01-17T09:19:22.000Z (over 5 years ago)
- Default Branch: master
- Last Pushed: 2024-10-16T17:10:47.000Z (over 1 year ago)
- Last Synced: 2024-10-18T10:20:06.922Z (over 1 year ago)
- Topics: daemon, fan, fan-speed, fancontrol, golang, hacktoberfest, pwm, rpm, temperature
- Language: Go
- Homepage:
- Size: 1.19 MB
- Stars: 227
- Watchers: 6
- Forks: 22
- Open Issues: 17
-
Metadata Files:
- Readme: README.md
- Funding: .github/FUNDING.yml
- License: LICENSE
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- stars - markusressel/fan2go
README
fan2go
A daemon to control the fans of your computer.
[]()
[](https://github.com/markusressel/fan2go/releases)
[](/LICENSE)
# Features
* [x] Intuitive YAML based configuration
* [x] Massive range of supported devices
* [x] lm-sensors (hwmon) based sensors and fans
* [x] Fans and temperature sensor on NVIDIA GPUs ([nvml](https://developer.nvidia.com/management-library-nvml))
* [x] File based fan/sensor for control/measurement of custom devices
* [x] Command based fan/sensor
* [x] Per fan user-defined speed curves
* [x] Fully customizable and composable curve definitions
* [x] Works after resume from suspend
* [x] **Stable** device paths after reboot
* [x] Automatic analysis of fan properties, like:
* [x] RPM curve
* [x] minimum and maximum PWM
* [x] Error notifications
* [x] Prometheus exporter
* [x] (optional) REST Api
# UI
fan2go is first and foremost a daemon that runs in the background. However, it also provides
a small set of CLI commands (see [CLI Commands](#cli-commands)) as well as an optional local HTTP API to allow
external programs to interact with it. This API can be used to create UI clients or other tools.
## UI Clients
[fan2go-tui](https://github.com/markusressel/fan2go-tui) - (Official) Terminal UI for fan2go.
[](https://asciinema.org/a/1099673)
# How to use
fan2go relies on [lm-sensors](https://github.com/lm-sensors/lm-sensors) to get both temperature and RPM sensor readings,
as well as PWM controls, so you will have
to [set it up first](https://wiki.archlinux.org/index.php/Lm_sensors#Installation).
## Installation
### Arch Linux 
```shell
yay -S fan2go-git
```
Community Maintained Packages
### Nix OS 
- Nix with [Flakes](https://nixos.wiki/wiki/Flakes):
```shell
nix profile install nixpkgs#fan2go
```
- Nix stable:
```shell
nix-env -f '' -iA fan2go
```
### Debian / Ubuntu
See: https://github.com/johnwbyrd/fan2go-package/
### Manual
Download the latest release from GitHub:
```shell
# Install dependencies
sudo pacman -S libnotify
curl -L -o fan2go https://github.com/markusressel/fan2go/releases/latest/download/fan2go-linux-amd64
chmod +x fan2go
sudo cp ./fan2go /usr/bin/fan2go
fan2go -h
```
Or compile yourself:
```shell
git clone https://github.com/markusressel/fan2go.git
cd fan2go
make build
sudo cp ./bin/fan2go /usr/bin/fan2go
sudo chmod ug+x /usr/bin/fan2go
```
## Configuration
Then configure fan2go by creating a YAML configuration file in **one** of the following locations:
* `/etc/fan2go/fan2go.yaml` (recommended)
* `/root/.fan2go/fan2go.yaml`
* `./fan2go.yaml`
```shell
sudo mkdir /etc/fan2go
sudo nano /etc/fan2go/fan2go.yaml
```
The most important configuration options you need to define are the `fans:`, `sensors:` and `curves:` sections.
### Fans
Under `fans:` you need to define a list of fan devices that you want to control using fan2go. To detect fans on your
system run `fan2go detect`, which will print a list of devices exposed by the hwmon filesystem backend:
```shell
$ fan2go detect
=========== hwmon: ============
> Platform: nct6798-isa-0290
Fans Index Channel Label RPM PWM Mode
1 1 hwmon4/fan1 0 153 Manual
2 2 hwmon4/fan2 1223 104 Manual
3 3 hwmon4/fan3 677 107 Manual
Sensors Index Label Value
1 SYSTIN 41000
2 CPUTIN 64000
> Platform: amdgpu-pci-0031
Fans Index Channel Label RPM PWM Mode
1 1 hwmon8/fan1 561 43 Manual
Sensors Index Label Value
1 edge 58000
2 junction 61000
3 mem 56000
=========== nvidia: ===========
> Device: nvidia-10DE2489-0800
Fans Index Label PWM RPM Mode
1 Fan 1 36 1300 Auto
2 Fan 2 36 1298 Auto
Sensors Index Label Value
1 Temperature 59000
```
The `hwmon` fan index is based on device enumeration and is not stable for a given fan if hardware configuration
changes.
The Linux kernel hwmon channel is a better identifier for configuration as it is largely based on the fan headers
in use.
Fan RPM, PWM, and temperature sensors are independent and Linux does not associate them automatically. A given PWM
may control more than one fan, and a fan may not be under the control of a PWM. By default, fan2go guesses and sets
the pwm channel number for a given fan to the fan's RPM sensor channel. You can override this in the config.
For `nvidia` devices, the fan index *is* stable.
Note that it can happen that the hardware only gives limited control over a fan and it, for example,
always runs with at least 30% speed - even if in automatic mode the hardware may make it stop entirely
if the temperature is low enough.
#### HwMon
To use detected hwmon devices in your configuration, use the `hwmon` fan type:
```yaml
# A list of fans to control
fans:
# A user defined ID.
# Used for logging only
- id: cpu
# The type of fan configuration, one of: hwmon | file
hwmon:
# A regex matching a controller platform displayed by `fan2go detect`, f.ex.:
# "nouveau", "coretemp", "it8620", "corsaircpro-.*" etc.
platform: nct6798
# The channel of this fan's RPM sensor as displayed by `fan2go detect`
rpmChannel: 1
# The pwm channel that controls this fan; fan2go defaults to same channel number as fan RPM
pwmChannel: 1
# Indicates whether this fan should never stop rotating, regardless of
# how low the curve value is
neverStop: true
# The curve ID that should be used to determine the
# speed of this fan
curve: cpu_curve
```
#### NVIDIA
To use detected NVIDIA GPUs in your configuration, use the `nvidia` fan type:
```yaml
fans:
- id: gpufan1
nvidia:
# A regex matching a nvidia device as displayed by `fan2go detect`
# the following matches all nvidia devices in your system
# (good enough if you only have one), otherwise you could
# also use nvidia-10DE2489-0800 or similar
device: nvidia
# The fan's index as shown by `fan2go detect`
index: 1
curve: gpu_curve
# same for the second fan
- id: gpufan2
nvidia:
device: nvidia
index: 2
curve: gpu_curve
```
Note that the fan speed can only be controlled for GPUs of the "Maxwell" generation
(Geforce 9xx) and newer, and that reading the fan speed in RPM requires nvidia driver 565
or newer.
#### File
```yaml
fans:
- id: file_fan
file:
# Path to a file to get/set the PWM target for this fan
path: /tmp/file_fan
# Path to a file to read the current RPM value of this fan
rpmPath: /tmp/file_fan_rpm
```
```shell
> cat /tmp/file_fan
255
> cat /tmp/file_fan_rpm
3421
```
#### CMD
Please also make sure to read the section about
[considerations for using the cmd sensor/fan](#using-external-commands-for-sensorsfans).
```yaml
fans:
- id: cmd_fan
cmd:
# Command to apply a new PWM value (0..255)
# Use "%pwm%" to specify where the target pwm value should be used within the arguments
setPwm:
exec: /usr/bin/some-program
args: [ "--set", "%pwm%" ]
# Command to retrieve the current PWM value (0..255)
getPwm:
exec: /usr/bin/nvidia-settings
args: [ "-a", "someargument" ]
# (optional) Command to retrieve the current RPM value
getRpm:
exec: /usr/bin/nvidia-settings
args: [ "-a", "someargument" ]
```
#### Disk
Reads the temperature of a block device (SATA, NVMe, etc.) using a stable device path instead of an
hwmon platform index that can change across reboots.
```yaml
sensors:
- id: ssd_temp
disk:
# Full path (recommended for clarity)
device: /dev/disk/by-id/ata-Samsung_SSD_870_EVO_1TB_S1234567890
# Short form also accepted (prefix /dev/disk/by-id/ is auto-applied):
# device: ata-Samsung_SSD_870_EVO_1TB_S1234567890
# The /dev/ prefix is also optional (e.g. just "sda"):
# device: sda
- id: nvme_temp
disk:
device: /dev/disk/by-id/nvme-Samsung_SSD_980_1TB_S1234567890
# Short form: device: nvme-Samsung_SSD_980_1TB_S1234567890
```
Requires the `drivetemp` kernel module for SATA drives (standard since kernel 5.6) or `nvme-hwmon`
for NVMe (standard since kernel 4.15). Falls back to a direct ATA SMART ioctl for SATA drives
without `drivetemp` loaded.
#### Advanced Options
If the automatic fan curve analysis doesn't provide a good enough estimation
for how the fan behaves, you can use the following configuration options (per fan definition)
to correct it:
```yaml
fans:
- id: ...
...
# (Optional) Override for the lowest PWM value at which the
# fan is able to maintain rotation if it was spinning previously.
minPwm: 30
# (Optional) Override for the lowest PWM value at which the
# fan will still be able to start rotating.
# Note: Settings this to a value that is too small
# may damage your fans. Use at your own risk!
startPwm: 30
# (Optional) Override for the highest PWM value which still yields
# an increased rotational speed compared to lower values.
# Note: you can also use this to limit the max speed of a fan.
maxPwm: 255
# (Optional) Override the global fanController.pwmSetDelay for this specific fan.
# Useful when a fan requires more or less time to respond to PWM changes than the global default.
# pwmSetDelay: 10ms
# (Optional) Configure how fan2go maps the internal [0..255] PWM range to
# hardware-specific PWM values. If omitted, fan2go auto-detects the mapping
# during fan initialization.
#
# Modes:
#
# autodetect (default): auto-detect the PWM map during fan initialization.
pwmMap: autodetect
#
# identity: assume a 1:1 mapping (0→0, 1→1, ..., 255→255).
# Use this if your fan supports the full PWM range and you want to skip
# the initialization measurement.
# pwmMap: identity
#
# linear: linearly interpolate between user-specified control points.
# Useful when you know the endpoints (or intermediate points) but want
# smooth values in between.
# Note: values must be strictly monotonically increasing.
# pwmMap:
# linear:
# 0: 0
# 255: 255
#
# values: step-interpolate user-specified control points.
# Use for fans that only support a limited set of discrete PWM values
# (e.g. off / low / medium / high).
# Note: values must be strictly monotonically increasing.
# pwmMap:
# values:
# 0: 0
# 64: 128
# 192: 255
# (Optional) Configure how fan2go determines the mapping from a PWM value it sets
# to the value the fan hardware reports back. Some fans do not echo the exact value
# written due to hardware or driver quirks. If omitted, fan2go auto-detects this
# during fan initialization.
#
# Modes:
#
# autodetect (default): sweep all PWM values and record what the fan reports back.
setPwmToGetPwmMap: autodetect
#
# identity: assume the fan reports back exactly what was set (1:1 mapping).
# Equivalent to the --assume-pwm-map-identity flag on `fan2go fan init`.
# setPwmToGetPwmMap: identity
#
# linear: linearly interpolate between user-specified control points.
# setPwmToGetPwmMap:
# linear:
# 0: 0
# 255: 255
#
# values: step-interpolate user-specified control points.
# setPwmToGetPwmMap:
# values:
# 0: 0
# 128: 128
# 255: 255
# (Optional) Configure the control mode fan2go uses while running and on exit.
# Both fields are optional; omitting controlMode entirely preserves existing behavior.
#
# active: the control mode to set when fan2go takes control of this fan.
# Accepts: "pwm" (default, with "disabled" fallback), "disabled", "auto", or an integer.
# onExit: what to do when fan2go exits.
# String shorthand:
# onExit: restore # restore original control mode (default)
# onExit: none # leave fan at last speed set by fan2go (useful for hardware controllers
# # that remember PWM settings — see issue #416)
# Map form (set explicit values on exit):
# onExit:
# mode: auto # set a specific control mode on exit
# speed: 128 # set a fixed PWM speed on exit (0..255)
# # controlMode and speed can be combined or used independently.
controlMode:
active: pwm
onExit: restore
# By default (useUnscaledCurveValues: false) speed values from the curve are scaled
# from 1..255 (or 1%..100%) to MinPwm..MaxPwm and speed values < 1(%) are set to 0,
# before they're mapped with pwmMap (the value looked up in pwmMap is then used to
# actually set the speed in the fan's controlling device).
# If useUnscaledCurveValues is set to true, the values from the curve for a specific temperature
# are directly mapped with PwmMap, *without* scaling them first.
# Note: If neverStop is also set to true, values smaller than MinPwm (including 0) are replaced with
# MinPwm, otherwise values smaller than MinPwm are replaced with 0 (the fan wouldn't turn anyway).
# But all values >= MinPwm are used as is if this option is set to true.
useUnscaledCurveValues: true
# (Optional) Configuration options for sanity checks
sanityCheck:
# (Optional) Control the behavior of the "pwmValueChangedByThirdParty" sanity check
# This check is used to detect if the PWM value of a fan has changed between two consecutive
# control loop cycles, which is usually an indication that an external program is trying to control the fan
# at the same time as fan2go. This can lead to unexpected behavior and is usually not desired, so
# fan2go will log a warning if this happens.
pwmValueChangedByThirdParty:
# (Optional) Whether to enable this check or not
enabled: true
# (Optional) Control the behavior of the "fanModeChangedByThirdParty" sanity check
# This check is used to detect if the fan mode (automatic/manual) has changed between two consecutive
# control loop cycles, which is usually an indication that an external program is trying to control the fan
# at the same time as fan2go. This can lead to unexpected behavior and is usually not desired, so
# fan2go will reset the desired fan mode and log a warning if this happens.
fanModeChangedByThirdParty:
# (Optional) Whether to enable this check or not
enabled: true
# (Optional) Throttle duration for the execution of this check.
throttleDuration: 10s
```
### Sensors
Under `sensors:` you need to define a list of temperature sensor devices that you want to monitor and use to adjust
fanspeeds. Like with fans, you can find usable devices using `fan2go detect`.
#### HwMon
```yaml
# A list of sensors to monitor
sensors:
# A user defined ID, which is used to reference
# a sensor in a curve configuration (see below)
- id: cpu_package
# The type of sensor configuration, one of: hwmon | nvidia | file | cmd | disk
hwmon:
# A regex matching a controller platform displayed by `fan2go detect`, f.ex.:
# "coretemp", "it8620", "corsaircpro-*" etc.
platform: coretemp
# The index of this sensor as displayed by `fan2go detect`
index: 1
```
#### NVIDIA
```yaml
sensors:
- id: gpu_temp
nvidia:
# A regex matching a nvidia device as displayed by `fan2go detect`
device: nvidia-10DE2489-0800
# The index of this sensor as displayed by `fan2go detect`
# (currently NVIDIA/nvml exposes only a single temperature sensor per GPU)
index: 1
```
#### File
```yaml
sensors:
- id: file_sensor
file:
# Path to the file containing sensor values
path: /tmp/file_sensor
```
The file contains a value in milli-units, like f.ex. milli-degrees.
```bash
> cat /tmp/file_sensor
10000
```
#### CMD
Please also make sure to read the section about
[considerations for using the cmd sensor/fan](#using-external-commands-for-sensorsfans).
Just like the `file` sensor, the command must output the sensor value in milli-units,
like f.ex. milli-degrees.
```yaml
sensors:
- id: cmd_fan
cmd:
# Path to the executable to run to retrieve the current sensor value
exec: /usr/bin/bash
# (optional) arguments to pass to the executable
args: [ '/home/markus/myscript.sh' ]
```
### Curves
Under `curves:` you need to define a list of fan speed curves, which represent the speed of a fan based on one or more
temperature sensors.
> **Speed values:** Curve values range from `0` to `255` (equivalently `0%` to `100%`).
> By default, fan2go scales these to the fan's detected (or configured) `minPwm`..`maxPwm` range:
> - `0` / `0%` → fan off (unless `neverStop: true`, in which case the fan is held at `minPwm`)
> - `1`..`255` / `1%`..`100%` → linearly mapped to `minPwm`..`maxPwm`
>
> To use curve values as raw PWM values without scaling, set `useUnscaledCurveValues: true` in the fan config.
#### Linear
To create a simple, linear speed curve, use a curve of type `linear`.
This curve type can be used with a min/max sensor value, where the min temp will result in a curve value of `0` and the
max temp will result in a curve value of `255`:
```yaml
curves:
- id: cpu_curve
# The type of the curve, one of: linear | function
linear:
# The sensor ID to use as a temperature input
sensor: cpu_package
# Sensor input value (in degrees Celsius)
# at which the curve is at minimum speed
min: 40
# Sensor input value at which the curve is at maximum speed
max: 80
```
You can also define the curve in multiple, linear sections using the `steps` parameter,
where the left side refers to the sensor input value and the right side refers to the curve value at that sensor input.
```yaml
curves:
- id: cpu_curve
# The type of the curve
linear:
# The sensor ID to use as a temperature input
sensor: cpu_package
# Steps to define a section-wise defined speed curve function.
steps:
# Sensor value (in degrees Celsius) -> Speed
- 40: 0% # 0% and speed value 0 are the same
- 41: 1% # 1% and speed value 1 are the same and mean "run at minimum speed" (MinPwm)
# Note: between 41 and 50°C the fan speed will be interpolated between 1% and 20%
- 50: 20% # 20% is equivalent to speed value ≈ 50
# Note: between 50 and 80°C the fan speed will be interpolated between 20% and 100%
# for example, at 65°C it'll run at 60% speed
- 80: 100% # 100% is equivalent to speed value 255
```
> NOTE: When using `useUnscaledCurveValues` in the fan configuration, the values specified in the curve are **not scaled
**
> to the [MinPwm..MaxPwm] range of the fan, but are directly mapped with the `pwmMap` (if specified) or used as is (if
> no `pwmMap` is specified and a 1:1 mapping is assumed).
> In this case, it is recommended to specify curve values in the same range as the expected PWM values after scaling to
> avoid confusion.
> So if your fan has a MinPwm of 30 and a MaxPwm of 255, you should specify curve values in the [30..255] range.
Alternatively the speeds can be specified in [0..255] range:
```yaml
curves:
- id: cpu_curve
# The type of the curve
linear:
# The sensor ID to use as a temperature input
sensor: cpu_package
# Steps to define a section-wise defined speed curve function.
steps:
# Sensor value (in degrees Celsius) -> Speed (0-255)
- 40: 0
- 41: 1
- 50: 50
- 80: 255
```
#### PID
If you want to get your hands dirty and use a PID based curve, you can use `pid`:
```yaml
curves:
- id: pid_curve
pid:
sensor: cpu_package
setPoint: 60
p: -0.05
i: -0.005
d: -0.005
```
Unlike the other curve types, this one does not use the average of the sensor data
to calculate its value, which allows you to create a completely custom behaviour.
Keep in mind though that the fan controller may also be PID based (depending on the
specified `controlAlgorithm`) which would also affect how the curve is applied to the fan.
`setPoint` is the target temperature.
See: [PID controller on Wikipedia](https://en.wikipedia.org/wiki/Proportional%E2%80%93integral%E2%80%93derivative_controller)
for more information on what a PID controller is.
#### Function
To create more complex curves you can combine existing curves using a curve of type `function`:
```yaml
curves:
- id: case_avg_curve
function:
# Type of aggregation function to use, one of: minimum | maximum | average | delta | sum | difference
type: average
# A list of curve IDs to use
curves:
- cpu_curve
- mainboard_curve
- ssd_curve
```
### Example
An example configuration file including more detailed documentation can be found in [fan2go.yaml](/fan2go.yaml).
### Verify your Configuration
To check whether your configuration is correct before actually running fan2go you can use:
```shell
> sudo fan2go config validate
INFO Using configuration file at: /etc/fan2go/fan2go.yaml
SUCCESS Config looks good! :)
```
or to validate a specific config file:
```shell
> fan2go -c "./my_config.yaml" config validate
INFO Using configuration file at: ./my_config.yaml
WARNING Unused curve configuration: m2_first_ssd_curve
ERROR Validation failed: Curve m2_ssd_curve: no curve definition with id 'm2_first_ssd_curve123' found
```
## Using external commands for sensors/fans
fan2go supports using external executables for use as both sensor input, as well as fan output (and rpm input). There
are some considerations you should take into account before using this feature though:
### Security
Since fan2go requires root permissions to interact with lm-sensors, executables run by fan2go are also executed as root.
To prevent some malicious actor from taking advantage of this fan2go will only allow the execution of files that only
allow the root user (UID 0) to modify the file.
### Side effects
Running external commands repeatedly through fan2go can have unintended side effects. F.ex., on a laptop using hybrid
graphics, running `nvidia-settings` can cause the dedicated GPU to wake up, resulting in substantial increase in power
consumption while on battery. Also, fan2go expects to be able to update sensor values with a minimal delay, so using a
long running script or some network call with a long timeout could also cause problems. With great power comes great
responsibility, always remember that :)
## Run
After successfully verifying your configuration you can launch fan2go from the CLI and make sure the initial setup is
working as expected. Assuming you put your configuration file in `/etc/fan2go/fan2go.yaml` run:
```shell
> fan2go help
fan2go is a simple daemon that controls the fans
on your computer based on temperature sensors.
Usage:
fan2go [flags]
fan2go [command]
Available Commands:
completion Generate the autocompletion script for the specified shell
config Configuration related commands
curve Curve related commands
detect Detect fans and sensors
fan Fan related commands
help Help about any command
sensor Sensor related commands
version Print the version number of fan2go
Flags:
-c, --config string config file (default is $HOME/.fan2go.yaml)
-h, --help help for fan2go
--no-color Disable all terminal output coloration
--no-style Disable all terminal output styling
-v, --verbose More verbose output
Use "fan2go [command] --help" for more information about a command.
> sudo fan2go
```
Alternatively you can specify the path to your configuration file like this:
```shell
> sudo fan2go -c /home/markus/my_fan2go_config.yaml
```
## As a Service
### Systemd
When installing fan2go using a package, it comes with a [systemd unit file](./fan2go.service). To enable it simply run:
```shell
sudo systemctl daemon-reload
sudo systemctl enable --now fan2go
# follow logs
journalctl -u fan2go -f
```
> NOTE: If you want to use a config path that differs from the default one, make sure to edit the
> unit file and point the `-c` flag to the correct path.
## CLI Commands
Although fan2go is a fan controller daemon at heart, it also provides some handy cli commands to interact with the
devices that you have specified within your config.
### Fans interaction
```shell
> fan2go fan --id cpu speed 100
> fan2go fan --id cpu speed
255
> fan2go fan --id cpu rpm
546
> fan2go fan --id cpu mode
No control, 100% all the time (0)
> fan2go fan --id cpu mode auto
Automatic control by integrated hardware (2)
```
### Sensors
```shell
> fan2go sensor --id cpu_package
46000
```
### Print fan curve data
For each newly configured fan **fan2go** measures its fan curve and stores it in a db for future reference. You can take
a look at this measurement using the following command:
```shell
> sudo fan2go fan --id cpu curve
cpu
Min PWM 30
Start PWM 30
Max PWM 255
No fan curve data yet...
> sudo fan2go fan --id in_front curve
nct6798 -> pwm2
Min PWM 0
Start PWM 0
Max PWM 194
1994 ┤ ╭────────────────────────
1900 ┤ ╭──╯
1805 ┤ ╭────╯
1711 ┤ ╭────╯
1616 ┤ ╭────╯
1522 ┤ ╭───╯
1427 ┤ ╭────╯
1333 ┤ ╭────╯
1238 ┤ ╭─────╯
1144 ┤ ╭────╯
1049 ┤ ╭─────╯
955 ┤ ╭─────╯
860 ┤ ╭─────╯
766 ┤ ╭─────╯
671 ┤ ╭─────╯
577 ┼─╯
RPM / PWM
```
## Statistics
fan2go has a prometheus exporter built in, which you can use to extract data over time. Simply enable it in your
configuration and you are good to go:
```yaml
statistics:
# Whether to enable the prometheus exporter or not
enabled: true
# The port to expose the exporter on
port: 9000
```
You can then see the metrics on [http://localhost:9000/metrics](http://localhost:9000/metrics) while the fan2go daemon
is
running.
## API
fan2go comes with a built-in REST Api. This API can be used by third party tools to display (and in the future possibly
modify) the state of fans, sensors and curves within fan2go.
```yaml
api:
# Whether to enable the API or not
enabled: false
# The host to listen for connections
host: localhost
# The port to listen for connections
port: 9001
```
### Endpoints
Currently, this API is read-only and only provides REST endpoints. If there is demand for it, this might be expanded to
also support realtime
communication via websockets.
#### Fans
| Endpoint | Type | Description |
|-------------|------|---------------------------------------------------|
| `/fan` | GET | Returns a list of all currently configured fans |
| `/fan/` | GET | Returns the fan with the given `id`, if it exists |
#### Sensors
| Endpoint | Type | Description |
|----------------|------|------------------------------------------------------|
| `/sensor` | GET | Returns a list of all currently configured sensors |
| `/sensor/` | GET | Returns the sensor with the given `id`, if it exists |
#### Curves
| Endpoint | Type | Description |
|---------------|------|-----------------------------------------------------|
| `/curve` | GET | Returns a list of all currently configured curves |
| `/curve/` | GET | Returns the curve with the given `id`, if it exists |
# How it works
## Device detection
fan2go uses [gosensors](https://github.com/md14454/gosensors) to directly interact with lm-sensors.
## Initialization
To properly control a fan which fan2go has not seen before, its RPM curve is analyzed.
fan2go uses an adaptive measurement process instead of sweeping all PWM values:
1. Discover the start boundary (`startPwm`) using boundary search.
2. Discover the max boundary (`maxPwm`) by scanning and confirming the upper PWM range.
3. Sample interior points coarsely between these boundaries.
4. Clean up the measured data by applying threshold-aware filtering, interpolation, monotonic enforcement, and interior
smoothing.
This produces a stable full-range PWM→RPM map while requiring far fewer measurements than a full linear sweep. Runtime
depends on fan response characteristics and the analysis config (`analysis.settleTimeout`, `analysis.sampleCount`,
`analysis.sampleDelay`, and `fanResponseDelay`).
All of this is saved to a local database (path given by the `dbPath` config option), so it is only needed once per fan
configuration.
To reduce risk while analyzing multiple fans, you can force fan2go to
initialize only one fan at a time, using the `runFanInitializationInParallel: false` config option.
Some PWM controllers or fans may require more time to react to PWM changes. If fan2go is failing to characterize a fan,
you can try increasing the fan response delay by passing `--fan-response-delay ` to the `fan init` command or
by setting `fanResponseDelay` in the config. The default value is 2 seconds.
## Monitoring
Temperature and RPM sensors are polled continuously at the rate specified by the `tempSensorPollingRate` config option.
`tempRollingWindowSize`/`rpmRollingWindowSize` amount of measurements are always averaged and stored as the average
sensor value.
## Fan Controllers
The speed of a Fan is controlled using a combination of its curve, a control algorithm and the properties of
the fan controller itself.
The curve is used as the target value for the control algorithm to reach. The control algorithm then calculates the
next PWM value to apply to the fan to reach this target value. The fan controller then applies this PWM value to the
fan, while respecting constraints like the minimum and maximum PWM values, as well as the `neverStop` flag.
### Cycle
A **cycle** refers to one iteration of a FanController's main control loop. fan2go creates one FanController per
configured fan, each running its own independent control loop.
During each cycle, the FanController:
1. Evaluates the fan's associated curve to determine the target PWM value
2. Runs the configured control algorithm (Direct or PID) to calculate the next PWM value
3. Applies constraints such as min/max PWM and the `neverStop` flag
4. Writes the PWM value to the hardware
5. Performs sanity checks (e.g. detecting third-party PWM interference)
The rate at which cycles execute is configured globally via `fanController.adjustmentTickRate` (default: `200ms`):
```yaml
fanController:
# The rate at which fan speed targets are updated
adjustmentTickRate: 200ms
```
This setting also determines the time unit implied by `maxPwmChangePerCycle` in the Direct control algorithm.
### Control Algorithms
A control algorithm
is a function that returns the next PWM value to apply based on the target value calculated by the curve. The simplest
control algorithm is the direct control algorithm, which simply forwards the target value to the fan.
#### Direct Control Algorithm
The simplest control algorithm is the direct control algorithm. It simply forwards the curve value to the fan
controller.
```yaml
fans:
- id: some_fan
...
controlAlgorithm: direct
```
This control algorithm can also be used to approach the curve value more slowly:
```yaml
fans:
- id: some_fan
...
controlAlgorithm:
direct:
maxPwmChangePerCycle: 10
```
### PID Control Algorithm
The PID control algorithm uses a PID loop to approach the target value. The default
configuration is pretty non-aggressive using the following values:
| P | I | D |
|-------|--------|---------|
| `0.3` | `0.02` | `0.005` |
If you don't like the default behaviour you can configure your own in the config:
```yaml
fans:
- id: some_fan
...
controlAlgorithm:
pid:
p: 0.3
i: 0.02
d: 0.005
```
The loop is advanced at a constant rate, determined by the [cycle rate](#cycle) (`fanController.adjustmentTickRate`),
which defaults to `200ms`.
See [PID controller on Wikipedia](https://en.wikipedia.org/wiki/Proportional%E2%80%93integral%E2%80%93derivative_controller)
for more information on what a PID controller is.
# FAQ
## Why are my SATA HDD drives not detected?
**TL;DR**: `modprobe drivetemp`
While _lm-sensors_ doesn't provide temperature sensors of SATA drives by default, you can use the kernel module
`drivetemp` to enable this. See [here](https://wiki.archlinux.org/title/Lm_sensors#S.M.A.R.T._drive_temperature)
## WARNING: PWM of `` was changed by third party!
If you see this log message while running fan2go, fan2go detected a change of the PWM value for the given fan
that was not caused by fan2go itself. This usually means that fan2go is not the only program controlling the fan
and something else (like f.ex. the mainboard or another fan control software) is also running and changing the speed
of the fan, competing with fan2go. Since fan2go cannot figure out what other software is, you have to investigate
this yourself.
Another common reason this message can occur is when the driver of the fan in question does not actually support
setting the PWM directly and uses some kind of virtual PWM instead. This has been a problem mostly on AMD graphics
cards but is probably not limited to them. See #64 for more detail.
If you are sure that this warning is not justified, you can disable this check on a per-fan basis.
See the `sanityCheck` section in the [fan configuration](#advanced-options) for more details.
## My components are overheating during initialization, what can I do about this?
**TL;DR**: Skip the initialization and configure your fans manually.
The initialization phase measures the RPM curve of each fan and tries to estimate the minimum and maximum
boundaries. This can take quite a while though and can lead to overheating of components if they are
under load. To avoid this use the `minPwm` and `maxPwm` fan config options to set the boundaries yourself.
That way the initialization phase will be skipped and the control algorithm will start right away.
# Dependencies
See [go.mod](go.mod)
# Similar Projects
* [nbfc-linux](https://github.com/nbfc-linux/nbfc-linux)
* [thinkfan](https://github.com/vmatare/thinkfan)
# License
```
fan2go
Copyright (C) 2021 Markus Ressel
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU Affero General Public License as published
by the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU Affero General Public License for more details.
You should have received a copy of the GNU Affero General Public License
along with this program. If not, see .
```