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List:       netbsd-port-i386
Subject:    Re: Surely cpumodel isn't cumulative?
From:       Stephen Borrill <netbsd () precedence ! co ! uk>
Date:       2009-11-30 16:02:04
Message-ID: Pine.NEB.4.64.0911301601140.4694 () ugly ! internal ! precedence ! co ! uk
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On Mon, 30 Nov 2009, Christoph Egger wrote:
>> On Mon, 30 Nov 2009, Stephen Borrill wrote:
>>>> From i386/coretemp.c:
>>>
>>>        cpumodel = CPUID2MODEL(ci->ci_signature);
>>>        /* extended model */
>>>        cpumodel += CPUID2EXTMODEL(ci->ci_signature);
>>>
>>> But EXTMODEL is extra detail within a given model, they
>>> can't be added together.
>>>
>>> i.e. model 0xe with ext model 0x1 is not the same as 0xf.
>>>
>>> Any unforeseen issues with just removing the second cpumodel
>>> line (or altering it to cpuextmodel)?
>>
>> This patch works for me on Xeon X3430:
>>
>> --- coretemp.c  25 Mar 2009 22:53:51 -0000      1.12
>> +++ coretemp.c  30 Nov 2009 15:28:40 -0000
>> @@ -67,7 +67,7 @@
>>          struct coretemp_softc *sc;
>>          uint32_t regs[4];
>>          uint64_t msr;
>> -       int cpumodel, cpumask;
>> +       int cpumodel, cpuextmodel, cpumask;
>>
>>          /*
>>           * CPUID 0x06 returns 1 if the processor has on-die thermal
>> @@ -85,7 +85,7 @@
>>              (int)device_unit(ci->ci_dev));
>>          cpumodel = CPUID2MODEL(ci->ci_signature);
>>          /* extended model */
>> -       cpumodel += CPUID2EXTMODEL(ci->ci_signature);
>> +       cpuextmodel = CPUID2EXTMODEL(ci->ci_signature);
>>          cpumask = ci->ci_signature & 15;
>
> On AMD you would write here:
>
>   if (cpumodel == 0xf)
>       cpumodel += cpuextmodel;
>
> and the hunk below would work unchanged.
> Check the Intel docs if you can do that on Intel, too.

No, you can't:

See page 16:
http://www.intel.com/Assets/en_US/PDF/specupdate/322373.pdf

-- 
Stephen

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