No fan RPM on some fans on MSI X870 Tomahawk

[nfp0]

This module seems to have exposed a lot of values for my MSI X870 Tomahawk motherboard, but some seem to be incorrect.

For example, the CPU Fan RPM is reading correctly, but the System Fan 2 and System Fan 3 should be reporting some RPM value, as I've confirmed they are rotating and the values are reading correctly on the BIOS.
A few temperature sensors also seem to be missing.

Here's the output of sensors after doing a sensors-detect:

nct6687-isa-0a20
Adapter: ISA adapter
+12V:           12.14 V  (min = +12.14 V, max = +12.17 V)
+5V:             5.06 V  (min =  +5.06 V, max =  +5.06 V)
+3.3V:           3.36 V  (min =  +0.00 V, max =  +3.36 V)
CPU Soc:         1.21 V  (min =  +1.21 V, max =  +1.22 V)
CPU Vcore:       1.09 V  (min =  +1.04 V, max =  +1.09 V)
CPU 1P8:         3.36 V  (min =  +3.36 V, max =  +3.36 V)
CPU VDDP:        3.36 V  (min =  +3.36 V, max =  +3.36 V)
DRAM:            1.41 V  (min =  +1.41 V, max =  +1.41 V)
Chipset:       332.00 mV (min =  +0.32 V, max =  +0.34 V)
CPU SA:        702.00 mV (min =  +0.70 V, max =  +0.71 V)
Voltage #2:      1.52 V  (min =  +1.52 V, max =  +1.52 V)
AVCC3:           3.30 V  (min =  +3.30 V, max =  +3.30 V)
AVSB:            3.36 V  (min =  +0.00 V, max =  +3.36 V)
VBat:            2.04 V  (min =  +0.00 V, max =  +2.04 V)
CPU Fan:        414 RPM  (min =  409 RPM, max =  414 RPM)
Pump Fan:         0 RPM  (min =    0 RPM, max =    0 RPM)
System Fan #1:    0 RPM  (min =    0 RPM, max =    0 RPM)
System Fan #2:    0 RPM  (min =    0 RPM, max =    0 RPM)
System Fan #3:    0 RPM  (min =    0 RPM, max =    0 RPM)
System Fan #4:    0 RPM  (min =    0 RPM, max =    0 RPM)
System Fan #5:    0 RPM  (min =    0 RPM, max =    0 RPM)
System Fan #6:    0 RPM  (min =    0 RPM, max =    0 RPM)
CPU:            +49.0°C  (low  = +48.0°C, high = +50.0°C)
System:         +45.0°C  (low  = +45.0°C, high = +45.0°C)
VRM MOS:        +46.0°C  (low  = +45.0°C, high = +46.0°C)
PCH:            +43.0°C  (low  = +42.0°C, high = +43.0°C)
CPU Socket:      +0.0°C  (low  =  +0.0°C, high =  +0.0°C)
PCIe x1:         +0.0°C  (low  =  +0.0°C, high =  +0.0°C)
M2_1:            +0.0°C  (low  =  +0.0°C, high =  +0.0°C)

[TheCompGeek]

Can confirm as well on an MSI MPG X870E CARBON WIFI board:

nct6687-isa-0a20
Adapter: ISA adapter
+12V:           12.29 V  (min = +12.26 V, max = +12.29 V)
+5V:             5.04 V  (min =  +5.04 V, max =  +5.04 V)
+3.3V:           3.34 V  (min =  +3.34 V, max =  +3.34 V)
CPU Soc:         1.31 V  (min =  +1.31 V, max =  +1.31 V)
CPU Vcore:       1.30 V  (min =  +1.30 V, max =  +1.30 V)
CPU 1P8:         3.34 V  (min =  +3.34 V, max =  +3.34 V)
CPU VDDP:        3.34 V  (min =  +3.34 V, max =  +3.34 V)
DRAM:            1.37 V  (min =  +1.37 V, max =  +1.37 V)
Chipset:         2.04 V  (min =  +2.04 V, max =  +2.04 V)
CPU SA:        422.00 mV (min =  +0.42 V, max =  +0.42 V)
Voltage #2:      1.54 V  (min =  +1.54 V, max =  +1.54 V)
AVCC3:           3.30 V  (min =  +3.30 V, max =  +3.30 V)
AVSB:            3.34 V  (min =  +3.34 V, max =  +3.34 V)
VBat:            2.04 V  (min =  +2.04 V, max =  +2.04 V)
CPU Fan:       1321 RPM  (min = 1320 RPM, max = 1321 RPM)
Pump Fan:         0 RPM  (min =    0 RPM, max =    0 RPM)
System Fan #1:    0 RPM  (min =    0 RPM, max =    0 RPM)
System Fan #2:    0 RPM  (min =    0 RPM, max =    0 RPM)
System Fan #3:    0 RPM  (min =    0 RPM, max =    0 RPM)
System Fan #4:    0 RPM  (min =    0 RPM, max =    0 RPM)
System Fan #5:    0 RPM  (min =    0 RPM, max =    0 RPM)
System Fan #6:    0 RPM  (min =    0 RPM, max =    0 RPM)
CPU:            +47.0°C  (low  = +47.0°C, high = +47.0°C)
System:         +49.5°C  (low  = +49.0°C, high = +49.5°C)
VRM MOS:        +38.5°C  (low  = +38.0°C, high = +38.5°C)
PCH:            +48.5°C  (low  = +48.5°C, high = +49.0°C)
CPU Socket:      +0.0°C  (low  =  +0.0°C, high =  +0.0°C)
PCIe x1:        +47.0°C  (low  = +47.0°C, high = +47.0°C)
M2_1:          +216.0°C  (low  = +216.0°C, high = +216.0°C)

[f8lxninja]

Confirmed on MSI PRO X870-P WIFI:

nct6687-isa-0a20
Adapter: ISA adapter
+12V:           12.22 V  (min = +12.19 V, max = +12.24 V)
+5V:             5.01 V  (min =  +4.98 V, max =  +5.02 V)
+3.3V:           3.34 V  (min =  +2.04 V, max =  +3.34 V)
CPU Soc:         1.31 V  (min =  +1.31 V, max =  +1.31 V)
CPU Vcore:       1.34 V  (min =  +1.32 V, max =  +1.35 V)
CPU 1P8:         3.34 V  (min =  +3.34 V, max =  +3.34 V)
CPU VDDP:        3.34 V  (min =  +3.33 V, max =  +3.34 V)
DRAM:            1.41 V  (min =  +1.41 V, max =  +1.42 V)
Chipset:       346.00 mV (min =  +0.33 V, max =  +0.35 V)
CPU SA:        778.00 mV (min =  +0.78 V, max =  +0.80 V)
Voltage #2:      1.53 V  (min =  +1.53 V, max =  +1.53 V)
AVCC3:           3.32 V  (min =  +3.32 V, max =  +3.33 V)
AVSB:            3.34 V  (min =  +0.00 V, max =  +3.34 V)
VBat:            2.04 V  (min =  +0.00 V, max =  +2.04 V)
CPU Fan:       1612 RPM  (min =    0 RPM, max = 2090 RPM)
Pump Fan:         0 RPM  (min =    0 RPM, max =    0 RPM)
System Fan #1:    0 RPM  (min =    0 RPM, max =    0 RPM)
System Fan #2:    0 RPM  (min =    0 RPM, max =    0 RPM)
System Fan #3:    0 RPM  (min =    0 RPM, max =    0 RPM)
System Fan #4:    0 RPM  (min =    0 RPM, max =    0 RPM)
System Fan #5:    0 RPM  (min =    0 RPM, max =    0 RPM)
System Fan #6:    0 RPM  (min =    0 RPM, max =    0 RPM)
CPU:            +53.0°C  (low  = +50.0°C, high = +67.0°C)
System:         +42.5°C  (low  = +41.0°C, high = +42.5°C)
VRM MOS:        +39.5°C  (low  = +38.5°C, high = +41.0°C)
PCH:            +38.5°C  (low  = +37.0°C, high = +38.5°C)
CPU Socket:      +0.0°C  (low  =  +0.0°C, high =  +0.0°C)
PCIe x1:         +0.0°C  (low  =  +0.0°C, high =  +0.0°C)
M2_1:            +0.0°C  (low  =  +0.0°C, high =  +0.0°C)

[demomanca]

Some of us are attempting to resolve this in the LibreHardwareMonitor project. It appears MSI has used some different pinouts on this motherboard than other implementations, and it doesn't appear to be as simple as "remapping them". Any assistance on this would be appreciated, as it seems to be effecting all the newer MSI boards using this chip (X870 and Z890)

[Fred78290]

@demomanca I don't have this motherboard.

[demomanca]

@demomanca I don't have this motherboard.

Sorry, I should have been clearer, it wasn't so much about that particular board, it was more about how you went about finding the registers etc, or is it a case of (as we have been doing) just trial, error, poke and prod.