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    SubjectRE: [PATCH 2/2] hwmon: (coretemp) Get TjMax value from MSR
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    CC Fenghua. 

    Could you found a Laptop with T5450 at hand? I can't found anywhere.

    -Huaxu

    On Mon, 2010-07-26 at 11:16 +0300, Maxim Levitsky wrote:
    > On Sun, 2010-06-13 at 10:27 +0800, Wan, Huaxu wrote:
    > > >On Wed, 2010-06-02 at 23:10 +0300, Maxim Levitsky wrote:
    > > >> On Wed, 2010-06-02 at 19:34 +0300, Maxim Levitsky wrote:
    > > >> > On Mon, 2010-05-31 at 09:39 +0800, Huaxu Wan wrote:
    > > >> > > On 08:39 Sat 29 May, Maxim Levitsky wrote:
    > > >> > > > On Fri, 2010-05-07 at 17:59 +0800, Huaxu Wan wrote:
    > > >> > > > > The MSR IA32_TEMPERATURE_TARGET contains the TjMax
    > > >value in the newer
    > > >> > > > > processers.
    > > >> > > >
    > > >> > > > I know that TjMax on my system is 85, and now coretemp
    > > >reports wrong
    > > >> > > > temperatures.
    > > >> > > > First of all BIOS using stupid tricks actualy reports
    > > >CPU temperature
    > > >> > > > through ACPI, and assuming it was correct TjMax is 85.
    > > >> > > > It also shuts down the system if I 'lie' to it that
    > > >cpu temperature is
    > > >> > > > 85C.
    > > >> > >
    > > >> > > From the list at [1], the TjMax(Tjunction) of T5450 is
    > > >100C. Does anyone
    > > >> > > here can make a double check?
    > > >> > >
    > > >> > > [1]
    > > >http://ark.intel.com/Product.aspx?id=30787&processor=T5450&spec
    > > >-codes=SLA4F
    > > >> >
    > > >> > This is very interesting.
    > > >> >
    > > >> > With TjMax 85C, the CPUs idle temperature is reported at
    > > >around 45~50C
    > > >> > GPU temperature that is around 50C
    > > >> >
    > > >> > BIOS also reports 45~50C.
    > > >> >
    > > >> > BIOS hooks an SMI to CPU thermal report, and stores the
    > > >temperature it
    > > >> > read in ram, then ACPI code reads it, reports and passes to the EC
    > > >> > (embedded controller).
    > > >> >
    > > >> > If I write myself 85 to embedded controller, systems shuts down.
    > > >> > (values less that 85, eg 84 don't shut system).
    > > >>
    > > >>
    > > >> Another clue is that right after resume from ram, after long delay
    > > >> (~hour) the displayed temperature with TjMax 85 is 33C. Since room
    > > >> temperature here is around 27C, this seems more plausible that
    > > >> 33 + 15 = 48C
    > > >
    > > >
    > > >Any update?
    > >
    > > I'm occupied by other things, sorry for slow response. But, as said in a
    > > spec, I can't remember which one now, there are too many, the relative
    > > value read from DTS is accurate approaching to TjMax. The accuracy
    > > deteriorates to +-10C at 50C. Any DTS reading below 50C should be
    > > considered to indicate only a temperature below 50C and not a specific
    > > temperature.
    > >
    > > So, the value around 50C can't be taken as real chip temperature. I
    > > would like this issue could be confirmed by more users to avoid it as a
    > > particular case. At the meantime, I still looking for a laptop with T5450,
    > > this may take some time.
    > >
    > > Thanks
    > > Huaxu
    >
    > Any update?
    >
    > Best regards,
    > Maxim Levitsky
    >




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