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Beemo

Member

Registered: 2024-12-20

Posts: 91

Dell OptiPlex: hwmon1/pwm1 stuck to 128

I'm trying to lower the fan speed of my Dell OptiPlex 7090 (Ideally 0 at idle and only turn on at higher temp).
It has an in-kernel driver with sysfs interface which lm-sensors can use. However, when trying pwmconfig it says "hwmon1/pwm1 stuck to 128", and indeed the value gets reverted even when manually editing the file.
How should I get fancontrol to work?

$ sudo sensors-detect
# sensors-detect version 3.6.2
# System: Dell Inc. OptiPlex 7090
# Board: Dell Inc. 0WV424
# Kernel: 7.0.14-arch1-1 x86_64
# Processor: 11th Gen Intel(R) Core(TM) i5-11500T @ 1.50GHz (6/167/1)
...
Do you want to generate /etc/conf.d/lm_sensors? (YES/no): no
To load everything that is needed, add this to one of the system
initialization scripts (e.g. /etc/rc.d/rc.local):

#----cut here----
# Chip drivers
modprobe coretemp
/usr/bin/sensors -s
#----cut here----

$ sensors
dell_smm-virtual-0
Adapter: Virtual device
fan1:        1791 RPM  (min =    0 RPM, max = 4000 RPM)
temp1:        +28.0°C
temp2:        +34.0°C
temp3:         +0.0°C
temp4:        +25.0°C
temp5:        +26.0°C
temp6:        +30.0°C
temp7:        +31.0°C
temp8:        +27.0°C
temp9:         +0.0°C
pwm1:             64%  MANUAL CONTROL

$ sudo pwmconfig
Found the following PWM controls:
   hwmon1/pwm1           current value: 128
hwmon1/pwm1 stuck to 128
Manual control mode not supported, skipping hwmon1/pwm1.
There are no usable PWM outputs.

$ cat pwm1_enable
1

Beemo

Member

Registered: 2024-12-20

Posts: 91

Re: Dell OptiPlex: hwmon1/pwm1 stuck to 128

Looking at the source, it doesn't have an entry for 7090, with support for 7080 recently added. Maybe it's also using the legacy interface and needs to be whitelisted?

EDIT: Added the entry similar to 7080 & compiled but does not work, might need custom data address like some others.

Last edited by Beemo (2026-07-04 09:27:39)