What the correct device id is, how to find it out?

[naddika]

Arch Linux, Think Pad yoga 11e

It won't run because the fan device is incorrect.

sudo systemctl status thinkfan

 thinkfan.service - simple and lightweight fan control program
     Loaded: loaded (/usr/lib/systemd/system/thinkfan.service; disabled; vendor preset: disabled)
    Drop-In: /etc/systemd/system/thinkfan.service.d
             └─override.conf
     Active: failed (Result: exit-code) since Wed 2021-06-23 21:40:27 +03; 1s ago
    Process: 52494 ExecStart=/usr/bin/thinkfan $THINKFAN_ARGS (code=exited, status=1/FAILURE)
        CPU: 5ms

Jun 23 21:40:27 user1 systemd[1]: Starting simple and lightweight fan control program...
Jun 23 21:40:27 user1 thinkfan[52494]: ERROR: Error scanning /sys/devices/pci0000:00/0000:00:03.1/0000:27:00.0/hwmon: No such file or directory
Jun 23 21:40:27 user1 systemd[1]: thinkfan.service: Control process exited, code=exited, status=1/FAILURE
Jun 23 21:40:27 user1 systemd[1]: thinkfan.service: Failed with result 'exit-code'.
Jun 23 21:40:27 user1 systemd[1]: Failed to start simple and lightweight fan control program.

How do I find out what the correct device is?

---

cat /usr/share/doc/thinkfan/examples/thinkfan.yaml

sensors:
  - hwmon: /sys/class/hwmon/hwmon0/temp1_input

  - hwmon: /sys/devices/pci0000:00/0000:00:03.1/0000:27:00.0/hwmon
    indices: [1, 2, 5, 6] # adds 4 temperature sensors
    correction: [0, 0, 0, -5] # add -5 °C to temp6_input

  - hwmon: /sys/class/hwmon
    name: k10temp
    indices: [1]

  - hwmon: /sys/class/block/sdc/device/hwmon
    indices: [1]
    optional: true # don't exit if the sensor can't be read

  - atasmart: /dev/sda

  - tpacpi: /proc/acpi/ibm/thermal
    indices: [1, 2, 3, 4]

  - nvml: 27:00.0

##############################################################################
# Fan Drivers
# ===========
#

fans:
  - hwmon: /sys/class/hwmon/hwmon0/pwm1

  - hwmon: /sys/class/graphics/fb0/device/hwmon
    indices: [1] # Use pwm1

  - hwmon: /sys/class/hwmon
    name: amdgpu
    indices: [1]

  - tpacpi: /proc/acpi/ibm/fan

##############################################################################
# Fan Speeds (simple mode)

levels:
  - [0, 0, 50]
  - ["level auto", 45, 75]
  - ["level disengaged", 70, 255]

##############################################################################
# Fan Speeds (detailed mode)
# ==========================

levels:
  - speed: 0
    upper_limit: [50, 50, 50]

  - speed: 100
    lower_limit: [45, 45, 45]
    upper_limit: [65, 65, 65]

  - speed: 255
    lower_limit: [60, 60, 60]

[vmatare]

Try running sensors as root to get a first overview and then go ahead and explore your /sys/class/hwmon directory. In case you've never looked at sysfs before: You basically just wanna output the contents of the various files in there, that'll give you an idea what's going on. Basically you're looking for files called temp*_input. Take a look at the manpage (man thinkfan.conf) and PLEASE DON'T just copy an example config. Figuring out why it doesn't work for you (it never will) is probably harder than reading the manpage and writing a correct one from scratch.

[vmatare]

Also very important documentation on /sys/class/hwmon: https://www.kernel.org/doc/html/latest/hwmon/sysfs-interface.html

[naddika]

I've run sensors. And this:

 tree /sys/class/hwmon
/sys/class/hwmon
├── hwmon0 -> ../../devices/LNXSYSTM:00/LNXSYBUS:00/ACPI0003:00/power_supply/ACAD/hwmon0
├── hwmon1 -> ../../devices/virtual/thermal/thermal_zone0/hwmon1
├── hwmon2 -> ../../devices/LNXSYSTM:00/LNXSYBUS:00/PNP0C0A:00/power_supply/BAT1/hwmon2
├── hwmon3 -> ../../devices/platform/thinkpad_hwmon/hwmon/hwmon3
├── hwmon4 -> ../../devices/virtual/thermal/thermal_zone1/hwmon4
├── hwmon5 -> ../../devices/platform/coretemp.0/hwmon/hwmon5
├── hwmon6 -> ../../devices/pci0000:00/0000:00:15.0/i2c_designware.0/i2c-0/i2c-WCOM5071:00/0018:056A:5074.0001/power_supply/wacom_battery_0/hwmon6
└── hwmon7 -> ../../devices/virtual/thermal/thermal_zone3/hwmon7

8 directories, 0 files

There's no temp*_input

[vmatare]

yeah, these are probably symlinks and it looks like your tree program isn't following them.

[vmatare]

take a look at the help with tree -h. You'll want to look at the -l option to make it follow symlinks and the -L option to limit the maximum depth. Try tree -l -L 2 /sys/class/hwmon for example.

[naddika]

% tree -l -L 2 /sys/class/hwmon
/sys/class/hwmon
├── hwmon0 -> ../../devices/LNXSYSTM:00/LNXSYBUS:00/ACPI0003:00/power_supply/ACAD/hwmon0
│   ├── device -> ../../ACAD
│   ├── name
│   ├── power
│   ├── subsystem -> ../../../../../../../class/hwmon  [recursive, not followed]
│   └── uevent
├── hwmon1 -> ../../devices/virtual/thermal/thermal_zone0/hwmon1
│   ├── device -> ../../thermal_zone0
│   ├── name
│   ├── power
│   ├── subsystem -> ../../../../../class/hwmon  [recursive, not followed]
│   ├── temp1_crit
│   ├── temp1_input
│   └── uevent
├── hwmon2 -> ../../devices/LNXSYSTM:00/LNXSYBUS:00/PNP0C0A:00/power_supply/BAT1/hwmon2
│   ├── device -> ../../BAT1
│   ├── in0_input
│   ├── name
│   ├── power
│   ├── subsystem -> ../../../../../../../class/hwmon  [recursive, not followed]
│   └── uevent
├── hwmon3 -> ../../devices/virtual/thermal/thermal_zone1/hwmon3
│   ├── device -> ../../thermal_zone1
│   ├── name
│   ├── power
│   ├── subsystem -> ../../../../../class/hwmon  [recursive, not followed]
│   ├── temp1_input
│   └── uevent
├── hwmon4 -> ../../devices/platform/thinkpad_hwmon/hwmon/hwmon4
│   ├── device -> ../../../thinkpad_hwmon
│   ├── fan1_input
│   ├── name
│   ├── power
│   ├── pwm1
│   ├── pwm1_enable
│   ├── subsystem -> ../../../../../class/hwmon  [recursive, not followed]
│   ├── temp10_input
│   ├── temp11_input
│   ├── temp12_input
│   ├── temp13_input
│   ├── temp14_input
│   ├── temp15_input
│   ├── temp16_input
│   ├── temp1_input
│   ├── temp2_input
│   ├── temp3_input
│   ├── temp4_input
│   ├── temp5_input
│   ├── temp6_input
│   ├── temp7_input
│   ├── temp8_input
│   ├── temp9_input
│   └── uevent
├── hwmon5 -> ../../devices/pci0000:00/0000:00:15.0/i2c_designware.0/i2c-0/i2c-WCOM5071:00/0018:056A:5074.0001/power_supply/wacom_battery_0/hwmon5
│   ├── device -> ../../wacom_battery_0
│   ├── name
│   ├── power
│   ├── subsystem -> ../../../../../../../../../../class/hwmon  [recursive, not followed]
│   └── uevent
├── hwmon6 -> ../../devices/virtual/thermal/thermal_zone2/hwmon6
│   ├── device -> ../../thermal_zone2
│   ├── name
│   ├── power
│   ├── subsystem -> ../../../../../class/hwmon  [recursive, not followed]
│   ├── temp1_input
│   └── uevent
└── hwmon7 -> ../../devices/platform/coretemp.0/hwmon/hwmon7
    ├── device -> ../../../coretemp.0
    ├── name
    ├── power
    ├── subsystem -> ../../../../../class/hwmon  [recursive, not followed]
    ├── temp1_crit
    ├── temp1_crit_alarm
    ├── temp1_input
    ├── temp1_label
    ├── temp1_max
    ├── temp2_crit
    ├── temp2_crit_alarm
    ├── temp2_input
    ├── temp2_label
    ├── temp2_max
    ├── temp3_crit
    ├── temp3_crit_alarm
    ├── temp3_input
    ├── temp3_label
    ├── temp3_max
    └── uevent

[naddika]

there're multiple temp*_input