[mythtv-users] Fan speed control using lm-sensors doesn't work.Help, please.

Johnny jarpublic at gmail.com
Wed Nov 18 15:28:41 UTC 2009

> k8temp-pci-00c3
> Adapter: PCI adapter
> Core0 Temp:  +51.0C
> Core0 Temp:  +42.0C
> Core1 Temp:  +47.0C
> Core1 Temp:  +35.0C
> it8716-isa-0e80
> Adapter: ISA adapter
> VCore:       +1.31 V  (min =  +0.00 V, max =  +4.08 V)
> VDDR:        +3.23 V  (min =  +0.00 V, max =  +4.08 V)
> +3.3V:       +0.00 V  (min =  +0.00 V, max =  +4.08 V)
> +5V:         +4.87 V  (min =  +0.00 V, max =  +6.85 V)
> +12V:       +12.10 V  (min =  +0.00 V, max = +16.32 V)
> in5:         +0.00 V  (min =  +0.00 V, max =  +4.08 V)
> in6:         +0.00 V  (min =  +0.00 V, max =  +4.08 V)
> 5VSB:        +6.85 V  (min =  +0.00 V, max =  +6.85 V)
> VBat:        +3.26 V
> fan1:       1380 RPM  (min =    0 RPM)
> fan2:          0 RPM  (min =    0 RPM)
> fan3:       1849 RPM  (min =    0 RPM)
> temp1:       +60.0C  (low  =  -1.0C, high = +127.0C)  sensor = thermal diode
> temp2:       +42.0C  (low  =  -1.0C, high = +127.0C)  sensor = transistor
> temp3:       +25.0C  (low  =  -1.0C, high = +127.0C)  sensor = transistor
> cpu0_vid:   +1.550 V


> What would you change?  Am I reading lm-sensors correctly?
> Allen

Unfortunately there are a number of issues that can make this
confusing. First these sensors aren't very accurate. Second the
lm-sensors software needs to be configured properly for a given
sensor/chip. It may be off by some constant offset, etc. Third, the
generic temperature labels make it hard to tell what sensor they go
with. Your reasoning is right though. The temperatures will be highest
at the core and go down as you move to the heatsink and case etc. The
k8temp sensors are the ones on your processor. Usually for each core
you have a core and a case temperature (CPU casing temp not the PC
case). The core temp is in the actual core and will be your highest
temp. The case temp is measure outside the core but in the CPU
package. So that is why you have two temps for each core.

It is tougher to say what temps the it8716 are referring to. The fact
that temp1 is higher than your core temperature implies it is not
calibrated/caculated correctly or it is measuring something else.
Temp2 looks like it is close to the CPU case temperature. Temp3 looks
in the right ball park for the motherboard or PC case temp. You can
get some clarification by using 'watch sensors' and then loading the
processor with something like cpuburn. Then see how the temperatures
change under load and see which one line up with the k8temps. When
most people give their CPU temps that are referring to the CPU case
temp. So your looks like it is around 40C. So you are fine.

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