This program calls undocumented functions of Dell SMM BIOS by defaults. USE ON YOUR OWN RISK
dell-fan-mon [OPTION]...
The dell-fan-mon is a daemon that monitors cpu / gpu temperatures, and controls the fan speed on some Dell laptops. It does that by means of regularly reading the system temperature, and choosing appropriate speed of the fans.
All options can be customized at /etc/dell-fan-mon.conf, or via command-line options
dell-fan-mon can access for temp and fan control with two modes (--mode <mode>):
-
mode 0: use dell-smm-hwmon(i8k) kernel module. This mode is more safety and can be used by unprivileged user.
-
mode 1: use direct SMM BIOS calls. To use this mode, dell-fan-mon needs root privileges. (default)
Please note: Disabling bios fan control use undocumented functions that were detected by blind brute force calls to SMM BIOS. There no any guaranty.
dell-fan-mon can try disable BIOS fan control with two methods(--bios_disable_method <method>):
-
method 0: don't disable bios. dell-fan-mon checks and controls fans state (see fan_check_period option) (default)
-
method 1: using code from https://github.com/clopez/dellfan
-
method 2: identical with https://github.com/TomFreudenberg/dell-bios-fan-control
To use this feature, dell-fan-mon needs root privileges.
Before set this option in config file, stop dell-fan-mon (sudo service dell-fan-mon stop)
and try every method in verbose mode (sudo dell-fan-mon -v --bios_disable_method 2 --fan_ctrl_logic_mode 0).
Wait until cpu temp will be greater t_mid and fans was on. If during cpu temp
lowering BIOS doesn't try change fan state: seems this method works.
If you cant disable bios fan control, please pay attention to fan_ctrl_logic_mode 1
On exit (SIGTERM, SIGINT) dell-fan-mon set fans speed to max and try to restore BIOS fan control with corresponding method
dell-fan-mon supports monitoring discrete GPU temp (--discrete_gpu_mode <mode>) with 3 modes:
-
mode 0: monitor cpu_temp only (for integrated GPU)
-
mode 1: use temp = max(cpu_temp, gpu_temp) in fan control logic (default)
-
mode 2: use separate fans control (for laptops with dedicated fan for discrete gpu)
dell-fan-mon supports two methods for obtaining GPU temp
- Using direct SMM BIOS calls(--mode 1) dell-fan-mon try to autodetect GPU temp sensor. If autodetection failed discrete_gpu_mode automatically switch to 0 (monitor cpu_temp only). If it happened for you: please use second method.
- Using third party console utility. Set get_gpu_temp_cmd options in config file. In this case you need provide command which output one line with one number (GPU temp)
mode 2 use gpu_fan_id option, that also attempts to automatically detect using the SMM BIOS (--mode 1). You can switch back to --mode 0 if you setting get_gpu_temp_cmd, fans_count and gpu_fan_id manualy (you can see gpu_fan_id value in verbose mode after successed autodetection)
If you have discrete GPU it's good idea to run dell-fan-mon in verbose mode to be sure that autodetection works fine.
dell-fan-mon has two modes of fans control logic(--fan_ctrl_logic_mode <mode>) regarding 3 temperature thresholds t_low, t_mid, t_high and corresponding fan states t_low_fan, t_mid_fan, t_high_fan:
-
mode 0: Default logic (with default t_*_fan)
-
When temperature rising:
if temp in [t_low,t_mid] and fan_state = OFF: fan_state = OFF
if temp > t_mid: fan_state = LOW
if temp > t_high: fan_state = HIGH -
When temperature lowering:
if temp < t_low: fan_state = OFF
if temp in [t_low,t_mid] and fan_state = LOW: fan_state = LOW
if temp in [t_low, t_high] and fan_state = HIGH: fan_state = HIGH
- Real code:
if (temp <= cfg.t_low) fan_state = cfg.t_low_fan;
else if (temp > cfg.t_high) fan_state = cfg.t_high_fan;
else if (temp >= cfg.t_mid) fan_state = fan_state > cfg.t_mid_fan ? fan_state : cfg.t_mid_fan;
-
- mode 1: Simple logic which allow BIOS to control fans. Stop/start
fans оnly at boundary temps
if temp < t_low: fan_state = t_low_fan
if temp > t_high: fan_state = t_high_fan
dell-fan-mon has buildin mechanism for detect abnormal cpu temp jumps: short(1-2 seconds) cpu temp jumps on +20/+30 celsius which are cause of starting fans. You can control it via --jump_temp_delta and --jump_timeout options.
To disable this feature set jump_temp_delta to 100.
dell-fan-mon accepts the following command-line options
-
-h, --help
Show help and current values of all options. Before showing help programm load /etc/dell-fan-mon.conf. So it can be used for config file validation. -
-v, --verbose
Report hardware status and program actions on stdout. -
-m, --monitor_only
Report hardware status on stdout in get_only mode. Enable verbose output. -
-d, --daemon
Reports child PID in stdout and detach from console. Please don't use this option, until you know what you do: current version of the startup scripts works only with default value. Default is 0 (foreground mode). -
-t, --test
Useful for scripts. If init code works without errors - exits with code 0, otherwise - outputs error in stdout and exits with code 1. -
--mode <mode>
Set mode for accessing temp and fan controls. Default is 1.
mode 0: use dell-smm-hwmon(i8k) kernel module
mode 1: use direct SMM BIOS calls (default) -
--discrete_gpu_mode <mode>
Monitoring mode of discrete GPU temp. Default is 1.
mode 0: monitor cpu_temp only(integrated GPU)
mode 1: use temp = max(cpu_temp, gpu_temp) in fan control logic (default)
mode 2: use separate fans control (for laptops with dedicated fan for discrete gpu) -
--fan_ctrl_logic_mode <mode>
Set fan control logic. Default is 0.
mode 0: default logic (see above)
mode 1: allow BIOS to control fans. Stop/start fans оnly at boundary temps(see above) -
--bios_disable_method <method>
Set disable BIOS fans control method. Not always works. Default is 0.
method 0: don't disablе BIOS fans control
method 1: use DISABLE_BIOS_METHOD1
method 2: use DISABLE_BIOS_METHOD2 -
--period <milliseconds>
Specifies the interval at which the daemon checks the hardware status. Default is 1000 milliseconds. -
--fan_check_period <milliseconds>
Specifies the interval at which the daemon checks the fans speed and set it. Used only when bios_disable_method 0. Default is 1000 milliseconds. -
--jump_timeout <milliseconds>
Specifies the interval at which the daemon ignore cpu temperature, after an abnormal temperature jump detected. Default is 2000 milliseconds. -
--jump_temp_delta <celsius>
Temperature difference between checks, at which the new value is considered abnormal. Default is 5° celsius. -
--t_low <celsius>
Temperature threshold "low" in celsius. Default is 45° celsius. -
--t_mid <celsius>
Temperature threshold "middle" in celsius. Default is 60° celsius. -
--t_high <celsius>
Temperature threshold "high" in celsius. Default is 80° celsius. -
--t_low_fan <fan_state_id>
Fan state corresponding to temperature threshold "low". Default is 0 (OFF). -
--t_mid_fan <fan_state_id>
Fan state corresponding to temperature threshold "middle". Default is 1 (LOW). -
--t_high_fan <fan_state_id>
Fan state corresponding to temperature threshold "high". Default is 2 (HIGH). -
--gpu_fan_id <fan_id> GPU fan_id, sometimes determined automatically through SMM BIOS. Used only when discrete_gpu_mode is 2. 0 = right, 1 = left. Default is 9 (autodetect).
-
--fans_count <number> Set number of fans in your device. Normally detected automatically through SMM BIOS. Default is 9 (autodetect).
dell-fan-mon has builtin default values of all options. User can see current values using --help option.
All options with double dash described before can be changed in /etc/dell-fan-mon.conf using same name.
/etc/dell-fan-mon.conf
ace (https://github.com/ru-ace)
Code for access to temp and fan control using dell-smm-hwmon(i8k) kernel
module from https://github.com/vitorafsr/i8kutils
Code for enable/disable BIOS fan control and direct SMM BIOS calls from
https://github.com/clopez/dellfan
git clone --depth 1 https://github.com/ru-ace/dell-fan-mon.git
cd dell-fan-mon
make
sudo make test
# no output is good.
# check if disabling bios works for you:
sudo ./dell-fan-mon -v --bios_disable_method 1
sudo ./dell-fan-mon -v --bios_disable_method 2
# wait until cpu temp will be greater t_mid(60°) and fans was on.
# If during cpu temp lowering BIOS doesn't try change fan state: seems this method works for you.
sudo make install
# edit /etc/dell-fan-mon.conf :
# set bios_disable_method which got earlier
# if bios_disable_method does not work for you: i recommends use fan_ctrl_logic_mode 1
# after config changed, lets check that no errors output on
sudo dell-fan-mon --test
sudo service dell-fan-mon restart
# I highly recommend first running dell-fan-mon in verbose mode for a while to make sure that it suits you.
sudo service dell-fan-mon stop
sudo dell-fan-mon -v
# if you decide to uninstall dell-fan-mon
sudo make uninstallQ: I got init_ioperm: Operation not permitted
A: Disable secure boot in bios. See issue 2
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