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

[Borislav Petkov]

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...

-- 
Regards/Gruss,
    Boris.

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