Arch Linux

the_jest

Member

Registered: 2022-02-07

Posts: 38

Can't adjust fan speed

I have a new install on a desktop system (using a non-cutting-edge mobo and the current kernel), and I seem to be unable to control the speed of the main case fan (which is "fan3" according to the sensors). The fan runs at about 1900 RPM, generating substantial noise. I can lower it to around 1300 RPM using a reducer cable, and this is a more appropriate noise level, but I'd of course like this to be controlled automatically: I wouldn't mind more noise when things are busy, and I'd prefer less noise when things are not. (The machine is rarely under heavy load.)

I've followed the Fan speed control wiki page to try to get this going, but I'm confused by the explanation in the pwmconfig output. Here's what I have; if more information is necessary I'll supply whatever I can.

The hardware/kernel:

$ sudo sensors-detect
# sensors-detect version 3.6.0+git
# Board: ASRock AB350 Gaming-ITX/ac
# Kernel: 5.16.2-arch1-1 x86_64
[etc.]

The "sensors" command reveals:

$ sensors
nct6792-isa-0290
Adapter: ISA adapter
[...]
fan1:                     0 RPM  (min =    0 RPM)
fan2:                  2067 RPM  (min =    0 RPM)
fan3:                  1869 RPM  (min =    0 RPM)
fan4:                     0 RPM  (min =    0 RPM)
fan5:                     0 RPM  (min =    0 RPM)
SYSTIN:                +117.0°C  (high =  +0.0°C, hyst =  +0.0°C)  sensor = thermistor
CPUTIN:                 +45.5°C  (high = +80.0°C, hyst = +75.0°C)  sensor = thermistor
AUXTIN0:                +41.0°C  (high =  +0.0°C, hyst =  +0.0°C)  ALARM  sensor = thermistor
AUXTIN1:               +107.0°C    sensor = thermistor
AUXTIN2:               +107.0°C    sensor = thermistor
AUXTIN3:               -128.0°C    sensor = thermistor
PCH_CHIP_CPU_MAX_TEMP:   +0.0°C  
PCH_CHIP_TEMP:           +0.0°C  
PCH_CPU_TEMP:            +0.0°C  
PCH_MCH_TEMP:            +0.0°C  
intrusion0:            OK
intrusion1:            ALARM
beep_enable:           disabled

Running "pwmconfig" gives:

$ sudo pwmconfig
# pwmconfig version 3.6.0+git
[...]
Found the following devices:
   hwmon0 is k10temp
   hwmon1 is iwlwifi_1
   hwmon2 is nct6792
   hwmon3 is hidpp_battery_4
   hwmon4 is hidpp_battery_4

Found the following PWM controls:
   hwmon2/pwm1           current value: 165
hwmon2/pwm1 is currently setup for automatic speed control.
In general, automatic mode is preferred over manual mode, as
it is more efficient and it reacts faster. Are you sure that
you want to setup this output for manual control? (n)
   hwmon2/pwm2           current value: 172
hwmon2/pwm2 is currently setup for automatic speed control.
In general, automatic mode is preferred over manual mode, as
it is more efficient and it reacts faster. Are you sure that
you want to setup this output for manual control? (n)
   hwmon2/pwm3           current value: 166
hwmon2/pwm3 is currently setup for automatic speed control.
In general, automatic mode is preferred over manual mode, as
it is more efficient and it reacts faster. Are you sure that
you want to setup this output for manual control? (n) 
   hwmon2/pwm4           current value: 127
   hwmon2/pwm5           current value: 127

Giving the fans some time to reach full speed...
Found the following fan sensors:
   hwmon2/fan1_input     current speed: 0 ... skipping!
   hwmon2/fan2_input     current speed: 2086 RPM
   hwmon2/fan3_input     current speed: 1875 RPM
   hwmon2/fan4_input     current speed: 0 ... skipping!
   hwmon2/fan5_input     current speed: 0 ... skipping!

Warning!!! This program will stop your fans, one at a time,
for approximately 5 seconds each!!!
This may cause your processor temperature to rise!!!
If you do not want to do this hit control-C now!!!
Hit return to continue: 

Testing pwm control hwmon2/pwm4 ...
  hwmon2/fan2_input ... speed was 2086 now 2083
    no correlation
  hwmon2/fan3_input ... speed was 1875 now 1877
    no correlation

No correlations were detected.
There is either no fan connected to the output of hwmon2/pwm4,
or the connected fan has no rpm-signal connected to one of
the tested fan sensors. (Note: not all motherboards have
the pwm outputs connected to the fan connectors,
check out the hardware database on http://www.almico.com/forumindex.php)

Did you see/hear a fan stopping during the above test (n)? 

Testing pwm control hwmon2/pwm5 ...
  hwmon2/fan2_input ... speed was 2086 now 2070
    no correlation
  hwmon2/fan3_input ... speed was 1875 now 1872
    no correlation

No correlations were detected.
There is either no fan connected to the output of hwmon2/pwm5,
or the connected fan has no rpm-signal connected to one of
the tested fan sensors. (Note: not all motherboards have
the pwm outputs connected to the fan connectors,
check out the hardware database on http://www.almico.com/forumindex.php)

Did you see/hear a fan stopping during the above test (n)? 

Testing is complete.
Please verify that all fans have returned to their normal speed.

To clarify, the fan speed did not change during this test. I'm afraid I don't understand the explanation in pwmconfig about the sensors, so I'd be grateful if someone could explain to me what I need to do.