Comment # 54 on bug 1185513 from Frank Kr���ger

(In reply to Joey Lee from comment #53)
> Hi Anthony, and anyone got the same problem.
> 
> On x86 platform, the _CPC affects intel_pstate drivers. Base on source code,
> the CPU priority based on ITMI (Intel Turbo Boost Max Technology) will not
> be set when _CPC is broken. Using no_hwp module parameter can disable the
> CPPC part in intel_pstate drivers, it may workaround issue.
> 
> Sorry for I am not familiar with intel_pstate driver, and I didn't find a
> _CPC machine yet. So I don't know what's the really affect to intel_pstate
> and CPU performance.
> 
> I will raise this situation on upstream.

JFYI https://bugzilla.kernel.org/show_bug.cgi?id=213023#c25