i8kmon/i8kfan for Dell Optiplex 7050 SFF desktop

i8kmon.py

#!/usr/bin/python3

import re
import subprocess
import time

# On my Dell Precision desktop, the `i8kmon` controls the fan level according to the ambient temperature, not the CPU temperature.
# Maybe the i8kutils only works for laptop? I don't know. Luckily, the `i8kfan` CAN control the motherboard fan and CPU fan.
# It's usage is `i8kfan - -`, the first number is for motherboard, the second for CPU. You should test the sequence first.

# Modified to only change CPU fan level, works on my Dell Optiplex 7050 SFF

# What this script do is simple: get temperatures from `/sys/class/hwmon`, and change the fan levels with `i8kfan`.

# CPU temperature threshold, level 1 and level 2
#  ------------ 50 -------------- 65 ----------
#  ---- 45 ------------ 55 ------------

# if temp is below L1_LOW, turn fan off.
# if temp is higher than L1_HIGH, turn fan on level 1, and last until temp drop to L1_LOW.
# same for L2.

CPU_L1_LOW = 45
CPU_L1_HIGH = 55
CPU_L2_LOW = 60
CPU_L2_HIGH = 70

CHECK_INTERVAL = 5
DEBUG = False

CPU_L1_LAST = False
CPU_L2_LAST = False


def log(Msg='none'):
    global DEBUG
    if DEBUG:
        print(time.strftime("%Y-%m-%d %H:%M:%S"),
              Msg)


def get_temp():
    coretemp_dir = '/sys/class/hwmon/hwmon3/temp1_input'
    try:
        with open(coretemp_dir, 'r') as coretemp_temp:
            CPUTemp = int(coretemp_temp.read().strip()) // 1000
    except:
        log("Error getting temperature.")
        return None

    temp_output = f'CPU: {CPUTemp}°C'
    log(temp_output)

    return CPUTemp


def set_fan(CPULevel=2):
    i8kfan_cmd = ['i8kfan', "-", str(CPULevel)]
    log(i8kfan_cmd)
    try:
        subprocess.call(i8kfan_cmd)
    except Exception as e:
        log(e)
        return None
    else:
        return True


def get_level(CPUTemp=80):
    global CPU_L1_LAST
    global CPU_L2_LAST

    global CPU_L1_LOW
    global CPU_L1_HIGH
    global CPU_L2_LOW
    global CPU_L2_HIGH
    
    CPULevel = 2

    # for CPU, fan flag
    if CPUTemp < CPU_L1_LOW:
        CPU_L1_LAST = False
    elif CPUTemp > CPU_L1_HIGH:
        CPU_L1_LAST = True

    if CPUTemp < CPU_L2_LOW:
        CPU_L2_LAST = False
    elif CPUTemp > CPU_L2_HIGH:
        CPU_L2_LAST = True

    # for CPU, fan level
    if CPUTemp < CPU_L1_LOW:
        CPULevel = 0
    elif CPUTemp < CPU_L1_HIGH:
        if CPU_L1_LAST == True:
            CPULevel = 1
        else:
            CPULevel = 0
    elif CPUTemp < CPU_L2_LOW:
        CPULevel = 1
    elif CPUTemp < CPU_L2_HIGH:
        if CPU_L2_LAST == True:
            CPULevel = 2
        else:
            CPULevel = 1
    else:
        CPULevel = 2

    return CPULevel


try:
    LastLevel = int(subprocess.check_output("i8kfan", stderr=subprocess.STDOUT,
                      shell=True, universal_newlines=True).strip().split(' ')[1])
except:
    LastLevel = -1

while True:
    CPUTemp = get_temp()
    if CPUTemp:
        CPULevel = get_level(CPUTemp)
        if CPULevel:
            if CPULevel != LastLevel:
                #r1 = set_fan(BoardLevel, CPULevel)
                r1 = set_fan(CPULevel)
                if not r1:
                    log('set fan error')
                    break
            else:
                log('fan level not change')
            LastLevel = CPULevel
        else:
            continue
    else:
        log('error get_temp()')
        continue
    time.sleep(CHECK_INTERVAL)