Re: [PATCH] ACPI: processor_idle: Skip dummy wait for processors based on the Zen microarchitecture

[Limonciello, Mario]

On 9/21/2022 14:51, Borislav Petkov wrote:
> On Wed, Sep 21, 2022 at 07:15:07AM -0700, Dave Hansen wrote:
> > In the end, the delay is because of buggy, circa 2006 chipsets?  So, we
> > use a CPU vendor specific check to approximate that the chipset is
> > recent and not affected by the bug?  If so, is there no better way to
> > check for a newer chipset than this?
>
> So I did some git archeology but that particular addition is in some
> conglomerate, glued-together patch from 2007 which added the cpuidle
> tree:
>
> commit 4f86d3a8e297205780cca027e974fd5f81064780
> Author: Len Brown <len.brown@xxxxxxxxx>
> Date:   Wed Oct 3 18:58:00 2007 -0400
>
>      cpuidle: consolidate 2.6.22 cpuidle branch into one patch
>
>
> so the most precise check here should be to limit that dummy read to
> that Intel chipset which needed it. Damned if I knew how to figure out
> which...

Functionally most Intel platforms use intel_idle though these days 
though, right?