Thinkpad Z16 Fan Control with Thinkfan

NOTE: This is how I configured thinkfan for my Thinkpad Z16 Gen 1 on Fedora 38. I don’t guarantee that this’ll work for any other machine.

Setup

Enable fan control. As root:

$ echo "options thinkpad_acpi fan_control=1" > /etc/modprobe.d/thinkfan.conf
$ modprobe thinkpad_acpi

And reboot.

Build thinkfan from source by following the instructions in the README. At the time of writing:
1. Install dependencies:
```
$ sudo dnf install -y cmake g++ pkgconfig yaml-cpp-devel lm_sensors-devel
```
2. Create a build folder:
```
$ mkdir build && cd build
```
3. Configure the build directory (make sure USE_LM_SENSORS and USE_YAML are set to ON):
```
$ ccmake ..
```
4. Compile
```
$ make
```
5. And Install
```
$ sudo make install
```

Create the config:

Run sensors-detect and sensors to find the correct name for the sensors. In my case, running sensors produced an output of:

thinkpad-isa-0000
Adapter: ISA adapter
fan1:        2364 RPM
fan2:        2219 RPM
CPU:          +44.0°C
GPU:              N/A
temp3:        +44.0°C
temp4:        +44.0°C
...

Note the names of all sensors shown, as well as the ids. In this case, that would be thinkpad-isa-0000 and [ CPU, temp3, temp4, etc. ].
Create /etc/thinkfan.conf and enter that info under sensors: (I’ll show my full configuration further down).
Add a section fans: and add tpacpi: /proc/acpi/ibm/fan.
Add a section levels: and put in fan levels in the format [ <fan_level>, <lower_limit_temp>, <upper_limit_temp> ]. For example, if I wanted to set fan level 4 from 55°C to 64°C, you would write [ 4, 55, 64 ].

My full config looks like this:

sensors:
  - chip: thinkpad-isa-0000
    ids: [ CPU, temp3, temp5, temp6, temp7 ]
  - chip: amdgpu-pci-6400
    ids: [ edge ]
  - chip: nvme-pci-0300
    ids: [ Composite ]

fans:
  - tpacpi: /proc/acpi/ibm/fan

# levels from https://wiki.gentoo.org/wiki/Fan_speed_control/thinkfan
levels:
  - [ 0, 0,  41 ]
  - [ 1, 38, 51 ]
  - [ 2, 45, 56 ]
  - [ 3, 51, 61 ]
  - [ 4, 55, 64 ]
  - [ 5, 60, 66 ]
  - [ 6, 63, 68 ]
  - [ 7, 65, 74 ]
  - [ "level full-speed", 70, 32767 ]

Run thinkfan to test your configuration.
Enable the systemd service:
```
$ sudo systemctl enable thinkfan
```

Why Did I Build From Source?

The version of thinkfan in the fedora repos seems to be built without lm_sensors support. So, if you installed it from dnf and tried running my configuration, you’d get a rather cryptic error message:

ERROR: /etc/thinkfan.yaml:2:
  - chip: thinkpad-isa-0000
    ^
Invalid sensor entry.

(See this issue, which is still applicable despite being about the AUR package).

Fan Speeds

Thinkpads’ have eight fan speed levels:

level 0: fans off
level 1
level 2: low speed
level 3
level 4: medium speed
level 5
level 6
level 7: high speed

And three special levels:

level auto: the default level where fan RPM is controlled by the BIOS
level full-speed: the maximum monitored speed
level disengaged: the true maximum speed where the embedded controller stops monitoring the fan speed

Manual Fan Speed Control

To control fan speed manually, just echo the intended level to /proc/acpi/ibm/fan. For example, to change the fan speed to level 4, run:

echo "level 4" > /proc/acpi/ibm/fan