custom fan control using i8kctl on alienware m15 with cachyos ( arch based linux )

custom_fan_control.sh

#!/bin/bash

# LOG_FILE="~/fan_control.log"

# Initialize last fan state
LAST_LEFT=-1
LAST_RIGHT=-1

while true; do
  # Get CPU temperature
  CPU_TEMP=$(sensors | awk '/^CPU:/ { gsub(/\+|°C/, "", $2); print int($2) }')

  # Get GPU temperature
  GPU_TEMP=$(nvidia-smi --query-gpu=temperature.gpu --format=csv,noheader,nounits)

  # Default fan levels
  LEFT=0  # CPU fan
  RIGHT=0 # GPU fan

  # Determine CPU fan speed
  if (( CPU_TEMP < 80 )); then
    LEFT=1  # Medium
  else
    LEFT=2  # High
  fi

  # Determine GPU fan speed
  if (( GPU_TEMP < 70 )); then
    RIGHT=1  # Medium
  else
    RIGHT=2  # High
  fi

  # Apply fan settings only if changed
  if [[ "$LEFT" -ne "$LAST_LEFT" ]]; then
    sudo /usr/bin/i8kctl fan1 $LEFT
    LAST_LEFT=$LEFT
  fi

  if [[ "$RIGHT" -ne "$LAST_RIGHT" ]]; then
    sudo /usr/bin/i8kctl fan2 $RIGHT
    LAST_RIGHT=$RIGHT
  fi

  echo "$(date): CPU Temp: $CPU_TEMP°C, GPU Temp: $GPU_TEMP°C, CPU Fan: $LEFT, GPU Fan: $RIGHT" >> $LOG_FILE

  sleep 5
done

run this:

sudo systemctl daemon-reexec
sudo systemctl daemon-reload
sudo systemctl restart custom_fan_control.service
sudo systemctl status custom_fan_control.service

Dont forget to set i8kctl run without sudo

sudo visudo

add this line, last line:
radia ALL=(ALL) NOPASSWD: /usr/bin/i8kctl

where radia is your username

UPDATE , after install fancontrol_ui

I dont know what happen, but now fan1 not working.

you need

which i8kctl

if on
/usr/local/bin/i8kctl

just replace the old

sudo mv /usr/local/bin/i8kctl /usr/bin/i8kctl

#!/bin/bash

# LOG_FILE="~/fan_control.log"

# Initialize last fan state
LAST_LEFT=-1
LAST_RIGHT=-1

while true; do
  # Get CPU temperature
  CPU_TEMP=$(sensors | awk '/^CPU:/ { gsub(/\+|°C/, "", $2); print int($2) }')

  # Get GPU temperature
  GPU_TEMP=$(nvidia-smi --query-gpu=temperature.gpu --format=csv,noheader,nounits)

  # Default fan levels
  LEFT=0  # CPU fan
  RIGHT=0 # GPU fan

  # Determine CPU fan speed
  if (( CPU_TEMP < 80 )); then
    LEFT=1  # Medium
  else
    LEFT=2  # High
  fi

  # Determine GPU fan speed
  if (( GPU_TEMP < 70 )); then
    RIGHT=1  # Medium
  else
    RIGHT=2  # High
  fi

  # Apply fan settings only if changed
  if [[ "$LEFT" -ne "$LAST_LEFT" ]]; then
    sudo /usr/bin/i8kctl fan $LEFT 0
    LAST_LEFT=$LEFT
  fi

  if [[ "$RIGHT" -ne "$LAST_RIGHT" ]]; then
    sudo /usr/bin/i8kctl fan 0 $RIGHT
    LAST_RIGHT=$RIGHT
  fi

  # echo "$(date): CPU Temp: $CPU_TEMP°C, GPU Temp: $GPU_TEMP°C, CPU Fan: $LEFT, GPU Fan: $RIGHT" >> $LOG_FILE

  sleep 5
done

If got error like this

$ i8kmon --help
can't find package cmdline 1.5
    while executing
"package require cmdline 1.5"
    (file "/usr/bin/i8kmon" line 20)
    

run this to search cmdline

pacman -Ql tcllib | grep cmdline.tcl

usually you got
/usr/lib/tcllib/cmdline/cmdline.tcl

then edit it

/usr/bin/i8kmon

add this to before import

lappend auto_path /usr/lib/tcllib

or you can test

lappend auto_path /usr/lib/tcllib
package require cmdline 1.5

Update:

sudo vim /etc/systemd/system/i8kmon.service

[Unit]
Description=Dell Fan Control Daemon (i8kmon)
After=multi-user.target

[Service]
Type=simple
ExecStart=/usr/bin/i8kmon
Restart=on-failure
User=root

[Install]
WantedBy=multi-user.target

sudo systemctl daemon-reload
sudo systemctl enable --now i8kmon.service

sudo systemctl status i8kmon.service

Bonus::

i8kctl fan
can't find package i8k::thermal
    while executing
"package require i8k::thermal"
    (file "/usr/bin/i8kctl" line 25)

sudo vim /usr/bin/i8kctl

lappend auto_path /usr/lib/tcl8/8.6