Problems with amd FX 8 core and freq scaling

[Jung-uk Kim]

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On 2013-11-11 16:31:30 -0500, Jung-uk Kim wrote:
> On 2013-11-11 15:26:58 -0500, Adrian Chadd wrote:
>> On 11 November 2013 12:00, Jung-uk Kim <jkim at freebsd.org> wrote:
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>>> 
>>> On 2013-11-11 13:16:47 -0500, Nicholas McKenzie wrote:
>>>> But wouldn't this just disable frequency scaling and the
>>>> whole point of powerd?
>>> 
>>> No.  acpi_throttle (and p4tcc) controls T-state.  "Frequency 
>>> scaling" should be done by changing P-state.
> 
>> Right.
> 
>> IIRC, T-state is just for emergency temperature throttling. It 
>> shouldn't be used outside of that.
> 
> 
>>>>> There have been a number of reports of throttling causing 
>>>>> crashes. This setting does not prevent powerd from
>>>>> adjusting your CPU's clock, it just disables some arcane
>>>>> feature which pre-dates the modern power management
>>>>> methods.
> 
>> .. did anyone ever figure out why crashes would be caused by 
>> T-state adjustment?
> 
> My memory is vague but I think it was not able to reject a broken
> FADT or _PTC table, or something like that.

Just in case, here I attached the uncommitted (and untested) patch.

Jung-uk Kim
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