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Subject: Re: [PATCH] ACPI: processor_idle: Skip dummy wait for processors
 based on the Zen microarchitecture
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To:     "Limonciello, Mario" <Mario.Limonciello@amd.com>,
        "Nayak, K Prateek" <KPrateek.Nayak@amd.com>,
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From:   Dave Hansen <dave.hansen@intel.com>
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On 9/22/22 10:48, Limonciello, Mario wrote:
> 
> 2) The title says to limit it to old intel systems, but nothing about this actually enforces that.
> It actually is limited to all Intel systems, but effectively won't be used on anything but new
> ones because of intel_idle.
> 
> As an idea for #2 you could check for CONFIG_INTEL_IDLE in the Intel case and
> if it's not defined show a pr_notice_once() type of message trying to tell people to use
> Intel Idle instead for better performance.

What does that have to do with *this* patch, though?

If you've got CONFIG_INTEL_IDLE disabled, you'll be slow before this
patch.  You'll also be slow after this patch.  It's entirely orthogonal.

I can add a "Practically" to the subject so folks don't confuse it with
some hard limit that is being enforced:

	ACPI: processor idle: Practically limit "Dummy wait" workaround to old
Intel systems

BTW, is there seriously a strong technical reason that AMD systems are
still using this code?  Or is it pure inertia?