Re: [PATCH v2 2/3] x86: Remove vendor checks from prefer_mwait_c1_over_halt

[Dave Hansen]

On 5/6/22 02:42, Wyes Karny wrote:
> 
> So, if CPUID.05H:ECX[0] = 0, MWAIT extensions are not available (not allowed) and hence 
> it is safe to use MWAIT with EAX=0,ECX=0. Otherwise, we have to check CPUID.05H:EDX[bit 7:4]
> to get the number of C1 substates and this should be greater than equal to 1.

Ahh, I misread the comment.  I was confusing the CPUID leaf ECX data
with the use of ECX hints to MWAIT.

Could you add maybe a sentence or two more in that comment to help
clarify the situation?