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    SubjectRe: Linux 2.6.25 (coretemp reads high temperatures)
    >
    > Hi all,
    >
    > I already answered this thread while ago. I can just confirm what Jean told.
    >
    >
    > >>>> I confirm this.
    > >>>> I *know* that temperatures reported now are wrong.
    > >
    > > And how do you know? The newly reported temperatures could be correct
    > > and the previous ones were incorrect (that's actually the case.) The
    > > thing is, the temperature is stored as a relative value in the CPU.
    > > Relative to what, depends on the CPU model, can be 85°C or 100°C. Up to
    > > kernel 2.6.24 we had a set of rules to find out, in 2.6.25 we have a
    > > presumably better heuristic. So some people have seen their CPU
    > > temperature climb by 15°C and others drop by 15°C, that's expected.
    >
    > Yes exactly. I decided to move to 0-100C scale, and move the limit too.
    > Of course some users with too low jumped to better scale some like you seems to
    > complain now.
    >
    >
    > >>> i have watercooling, and well :P when i touch the "tube", its normal
    > >>> room temperature, and believe me, i would notice if it was 45.. this is
    > >>> with my cpu at idle - at full load on all 4 cores, temp2 says 35, and
    > >>> ~60 on coretemp, and THIS i would surely be able to notice over room
    > >>> temp :)
    > >
    > > The coretemp driver reports the CPU _core_ temperature. That's not
    > > something you can touch, believe me (unless you are an electron.)
    > >
    > > Also note that the CPU temperature reported by the IT8718F may or may
    > > not match the reality. To make sure, you'd need to know the type of
    > > thermal diode expected by the IT8718F, the type of thermal diode in
    > > your CPU, compute the correction factor if there is one. And you'd need
    > > to know where the thermal diode is exactly. It is most certainly built
    > > into the CPU, but some motherboard makers are doing weird things.
    > >
    > > 22°C seems very low to me, even for water-cooling. Note that
    > > non-linearity of thermal diodes makes measurements inaccurate as they
    > > get away from the expected operating point. I guess that thermal diodes
    > > used in CPUs are calibrated for best results around the expected
    > > temperature when using air-cooling, rather than water-cooling.
    > >
    > >>> any progress on this bug?
    > >
    > > I still need to be convinced that there is a bug here.
    >
    > It is not a bug, a max limit changed too, it is just matter how to scale it. The
    > temperature is non-physical so comparing it to physical temperature does not
    > make any sense. I'm sorry I did not invent this relative temp stuff - Complain
    > @intel. They have some calibration of TjMAX for mobiles, but this bit does not
    > work for desktops/servers. I tried really hard to get at LEAST some
    > documentation so the driver looks like it looks. And not
    > guessed/guessed/guessed/how it looked earlier.
    >
    >
    > >
    > >>>> The reason is that bios did report same temperatures as coretemp in 2.6.24,
    > >>>> moreover some time ago I have run a cpu tool (don't remember its name) on windows
    >
    > It was most likely coretemp - I'm in contact with the guy. We share infos.
    >
    >
    > >>>> temperature of both cores
    > >>>> (I had to run this on windows - intel haven't released
    > >>>> drivers for their QST for temperature monitoring from bios - very sad)
    > >>>>
    > >>>> And the driver did say in kernel log that TJMAX is 85C
    > >
    > > Which driver, which kernel? As I wrote above, the coretemp heuristic
    > > changed in kernel 2.6.25, so the fact that a previous kernel was
    > > reporting a different tjmax value is irrelevant. Unless you have
    > > additional documentation from Intel, I would tend to believe that the
    > > coretemp driver in 2.6.25 is correct. But feel free to report the exact
    > > CPU model you have (with CPUID info) to Rudolf, if he gets enough
    > > reports about a specific CPU model which most people believe gets the
    > > wrong tjmax, he can fix the driver.
    >
    > Well again, I tried hard at Intel and I really could not get any info on some
    > calibration bit. The temperature is non-physical on arbitrary scale. I changed
    > that so for some people it jumped to 100C, for some it remained.
    >
    >
    > >>>> Lets at least make a kernel option to override tjmax?
    > >
    > > That's a possibility for sure, but what we would really need is to
    > > adjust the coretemp driver heuristics to always get it right - if
    > > that's not already the case, that is. I'll let Rudolf decide anyway.
    >
    > Well again, Intel swears there is no way how to get the TjMAX for
    > desktops/servers. It sucks but this is not my fault.
    >
    > Thanks,
    > Rudolf
    >


    Hi Rudolf, hi @ all,

    so we were just too concerned all the time & even though the
    temperatures seem too high there's nothing to worry ?

    I'd be more tranquilized if I had the old temperatures ;)
    but like lm_sensors's output states - it's not bad until I / we're
    getting temperatures from 85°C (?) [in this particular case], ...


    @lkml, Linus:

    sorry for all the noise ;)



    Len,

    here's the output of sensors (lm_sensors):

    with acpi thermal-support compiled in:

    w83627ehf-isa-0290
    Adapter: ISA adapter
    VCore: +1.12 V (min = +0.00 V, max = +1.74 V)
    in1: +12.36 V (min = +13.46 V, max = +13.46 V) ALARM
    AVCC: +3.34 V (min = +4.08 V, max = +2.03 V) ALARM
    3VCC: +3.34 V (min = +3.92 V, max = +3.95 V) ALARM
    in4: +1.70 V (min = +1.53 V, max = +2.04 V)
    in5: +1.59 V (min = +2.04 V, max = +1.02 V) ALARM
    in6: +5.12 V (min = +6.53 V, max = +6.32 V) ALARM
    VSB: +3.26 V (min = +3.06 V, max = +4.08 V)
    VBAT: +3.20 V (min = +4.02 V, max = +4.02 V) ALARM
    in9: +1.61 V (min = +2.04 V, max = +2.04 V) ALARM
    Case Fan: 0 RPM (min = 0 RPM, div = 128)
    CPU Fan: 969 RPM (min = 0 RPM, div = 8)
    Aux Fan: 3970 RPM (min = 0 RPM, div = 2)
    fan4: 0 RPM (min = 83 RPM, div = 128) ALARM
    fan5: 1308 RPM (min = 0 RPM, div = 8)
    Sys Temp: +39.0°C (high = +123.0°C, hyst = -65.0°C) sensor = thermistor
    CPU Temp: +29.0°C (high = +80.0°C, hyst = +75.0°C) sensor = diode
    AUX Temp: +121.5°C (high = +80.0°C, hyst = +75.0°C) ALARM sensor
    = thermistor
    cpu0_vid: +1.350 V

    coretemp-isa-0000
    Adapter: ISA adapter
    Core 0: +60.0°C (high = +84.0°C, crit = +100.0°C)

    coretemp-isa-0001
    Adapter: ISA adapter
    Core 1: +57.0°C (high = +84.0°C, crit = +100.0°C)

    -----------------------------------------------------------------------------------------------------------------------------------------------------------------------

    and without:

    w83627ehf-isa-0290
    Adapter: ISA adapter
    VCore: +1.30 V (min = +0.00 V, max = +1.74 V)
    in1: +12.30 V (min = +13.46 V, max = +13.46 V) ALARM
    AVCC: +3.36 V (min = +4.08 V, max = +2.03 V) ALARM
    3VCC: +3.34 V (min = +3.92 V, max = +3.95 V) ALARM
    in4: +1.70 V (min = +1.53 V, max = +2.04 V)
    in5: +1.59 V (min = +2.04 V, max = +1.02 V) ALARM
    in6: +5.12 V (min = +6.53 V, max = +6.32 V) ALARM
    VSB: +3.26 V (min = +3.06 V, max = +4.08 V)
    VBAT: +3.20 V (min = +4.02 V, max = +4.02 V) ALARM
    in9: +1.61 V (min = +2.04 V, max = +2.04 V) ALARM
    Case Fan: 0 RPM (min = 0 RPM, div = 128)
    CPU Fan: 986 RPM (min = 0 RPM, div = 8)
    Aux Fan: 3970 RPM (min = 0 RPM, div = 2)
    fan4: 0 RPM (min = 83 RPM, div = 128) ALARM
    fan5: 1308 RPM (min = 0 RPM, div = 8)
    Sys Temp: +39.0°C (high = +123.0°C, hyst = -65.0°C) sensor = thermistor
    CPU Temp: +29.0°C (high = +80.0°C, hyst = +75.0°C) sensor = diode
    AUX Temp: +117.0°C (high = +80.0°C, hyst = +75.0°C) ALARM sensor
    = thermistor
    cpu0_vid: +1.375 V

    coretemp-isa-0000
    Adapter: ISA adapter
    Core 0: +60.0°C (high = +84.0°C, crit = +100.0°C)

    coretemp-isa-0001
    Adapter: ISA adapter
    Core 1: +58.0°C (high = +84.0°C, crit = +100.0°C)

    -----------------------------------------------------------------------------------------------------------------------------------------------------------------------

    it's the completely same temperatures - it had no effect on the
    "correctness" of the output


    thanks to everyone

    Regards

    Mat
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