Re: [lm-sensors] Gigabyte GA-MA69G-S3H it8716 temperatures?

[Jean Delvare <khali@linux-fr.org>]

Hi Jon,

On Mon, 24 Nov 2008 09:27:08 +0000, Jon Hewer wrote:
> The output of sensors for my Gigabyte GA-MA69G-S3H motherboard is as follows:
> 
> k8temp-pci-00c3
> Adapter: PCI adapter
> Core0 Temp:   -6.0°C
> Core0 Temp:   +1.0°C
> Core1 Temp:   -8.0°C
> Core1 Temp:   -5.0°C
> 
> it8716-isa-0228
> Adapter: ISA adapter
> VCore:       +1.18 V  (min =  +0.00 V, max =  +4.08 V)
> VDDR:        +1.94 V  (min =  +0.00 V, max =  +4.08 V)
> +3.3V:       +3.25 V  (min =  +0.00 V, max =  +4.08 V)
> +5V:         +4.92 V  (min =  +0.00 V, max =  +6.85 V)
> +12V:       +12.10 V  (min =  +0.00 V, max = +16.32 V)
> in5:         +3.14 V  (min =  +0.00 V, max =  +4.08 V)
> in6:         +0.10 V  (min =  +0.00 V, max =  +4.08 V)
> 5VSB:        +4.92 V  (min =  +0.00 V, max =  +6.85 V)
> VBat:        +3.10 V
> fan1:       1341 RPM  (min =    0 RPM)
> fan2:       1002 RPM  (min =    0 RPM)
> temp1:       +33.0°C  (low  = +127.0°C, high = +60.0°C)  sensor = transistor
> temp2:       +25.0°C  (low  = +127.0°C, high = +127.0°C)  sensor = transistor
> temp3:       +19.0°C  (low  = +127.0°C, high = +60.0°C)  sensor = thermal diode
> cpu0_vid:   +1.200 V

Preliminary note: the "transistor" above should read "thermistor",
that's a bug in the it87 driver which has been fixed already.

> Firstly, I am trying to identify the three temperature readings
> returned by the it8716 module.  I have checked the sensors.conf and
> there is a note saying that it is motherboard specific.  I have
> contacted the manufacturer of my motherboard, but they haven't been
> able to help.
> 
> Has anybody else been able to identify which readings these are?  I'm
> guessing temp1=northbridge, temp2=cpu and temp3=system...

As a rule of thumb, CPU temperature is most often measured by a thermal
diode and motherboard temperature by a thermistor. That would be
temp1=system and temp3=cpu. That being said, I have to admit that 19
degrees C is very low for CPU temperature, unless it is water-cooled.

A quick test you can do to find out who is who is to put significant
load on the CPU (for example, "md5sum /dev/zero" running twice in
parallel for a dual-core CPU) and see which temperature is rising
faster. That will be the CPU temperature.

You can also compare the readings in the BIOS with those returned by
"sensors" under Linux. The readings in the BIOS should be equivalent to
those of "sensors" under moderate load.

Also note that Gigabyte has a long record of doing nasty things with
temperature sensors. For example, temp2 reads 25 degrees C... did it
ever change? On many Gigabyte boards, one temperature input is
connected to a simple resistor instead of a thermistor, so it reads 25
degrees C all the time. Such inputs should be ignored by adding "ignore
temp2" in sensors.conf.

> Secondly, the core temps returned by the k8temp module look a bit odd.
>  Am I just misunderstanding these readings, or do I need to tweak my
> conf?

This is a hardware issue, many K8 rev. F and later have broken sensors.
There's nothing we can do. Please send the contents of /proc/cpuinfo,
when we have enough data we might be able to blacklist the CPU models
that are known to be broken.

-- 
Jean Delvare

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