Re: [lm-sensors] [PATCH] x86/hwmon: fix initialization of coretemp

From: Jan Beulich
Date: Tue Sep 14 2010 - 02:44:22 EST


>>> On 14.09.10 at 08:34, Chen Gong <gong.chen@xxxxxxxxxxxxxxx> wrote:
> ä 9/13/2010 6:17 PM, Jan Beulich åé:
>> Using cpuid_eax() to determine feature availability on other than
>> the current CPU is invalid. And feature availability should also be
>> checked in the hotplug code path.
>>
>> Signed-off-by: Jan Beulich<jbeulich@xxxxxxxxxx>
>> Cc: Rudolf Marek<r.marek@xxxxxxxxxxxx>
>>
>> ---
>> arch/x86/include/asm/cpufeature.h | 1 +
>> arch/x86/kernel/cpu/scattered.c | 1 +
>> drivers/hwmon/coretemp.c | 29 +++++++++++++----------------
>> 3 files changed, 15 insertions(+), 16 deletions(-)
>>
>> --- linux-2.6.36-rc4/arch/x86/include/asm/cpufeature.h 2010-09-13
> 08:44:55.000000000 +0200
>> +++
> 2.6.36-rc4-x86-coretemp-feature-check/arch/x86/include/asm/cpufeature.h 20
> 10-09-01 09:18:17.000000000 +0200
>> @@ -168,6 +168,7 @@
>> #define X86_FEATURE_XSAVEOPT (7*32+ 4) /* Optimized Xsave */
>> #define X86_FEATURE_PLN (7*32+ 5) /* Intel Power Limit Notification */
>> #define X86_FEATURE_PTS (7*32+ 6) /* Intel Package Thermal Status */
>> +#define X86_FEATURE_DTS (7*32+ 7) /* Digital Thermal Sensor */
>
> Do we really need a new CPU flag ?

We don't strictly need one, but for one it parallels X86_FEATURE_PTS,
and it allows easy identification of the feature's availability from user
space.

Jan
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