hwmon: (coretemp) Get TjMax value from MSR
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From: Maxim Levitsky on 12 Jun 2010 09:10 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 60C > > > > 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? > > > Best regards, > Maxim Levitsky > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Wan, Huaxu on 12 Jun 2010 22:40
>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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |