linux-kernel - Re: [PATCH] ACPI: Only evaluate the Intel _OSC and

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Date: Tue, 18 Jun 2024 21:46:47 +0200
From: "Rafael J. Wysocki" <rafael@...nel.org>
To: Mario Limonciello <mario.limonciello@....com>
Cc: "Rafael J. Wysocki" <rafael@...nel.org>, "open list:ACPI" <linux-acpi@...r.kernel.org>, 
	open list <linux-kernel@...r.kernel.org>, 
	PradeepVineshReddy Kodamati <PradeepVineshReddy.Kodamati@....com>, CL Lin <clin41@...ovo.com>
Subject: Re: [PATCH] ACPI: Only evaluate the Intel _OSC and _PDC on platforms
 with HWP

On Tue, Jun 18, 2024 at 9:33 PM Mario Limonciello
<mario.limonciello@....com> wrote:
>
> On 6/15/2024 05:38, Rafael J. Wysocki wrote:
> > On Fri, Jun 14, 2024 at 9:33 PM Mario Limonciello
> > <mario.limonciello@....com> wrote:
> >>
> >> The UUID 4077A616-290C-47BE-9EBD-D87058713953 and _PDC methods are
> >> only used on Intel platforms with HWP support.
> >
> > I beg to differ.  See arch_acpi_set_proc_cap_bits() definition.
>
> Ah I see; thanks for sharing.  I agree with you.
>
> >
> >> Attempting to evaluate them and showing messages on hardware without
> >> HWP is pointless needlessly noisy.
> >>
> >> Gate the code on X86_FEATURE_HWP.
> >
> > Not really.
>
> I guess this really started getting noisy in 6.6 (9527264).
>
> Would you be open to downgrading to debug instead?

That would be fine, thanks!


> >
> >> Cc: PradeepVineshReddy (Pradeep Vinesh Reddy) Kodamati <PradeepVineshReddy.Kodamati@....com>
> >> Suggested-by: CL Lin <clin41@...ovo.com>
> >> Signed-off-by: Mario Limonciello <mario.limonciello@....com>
> >> ---
> >>   drivers/acpi/acpi_processor.c | 2 ++
> >>   1 file changed, 2 insertions(+)
> >>
> >> diff --git a/drivers/acpi/acpi_processor.c b/drivers/acpi/acpi_processor.c
> >> index 7a0dd35d62c9..84848b5e65d6 100644
> >> --- a/drivers/acpi/acpi_processor.c
> >> +++ b/drivers/acpi/acpi_processor.c
> >> @@ -597,6 +597,8 @@ static bool __init acpi_early_processor_osc(void)
> >>
> >>   void __init acpi_early_processor_control_setup(void)
> >>   {
> >> +       if (!boot_cpu_has(X86_FEATURE_HWP))
> >> +               return;
> >>          if (acpi_early_processor_osc()) {
> >>                  pr_info("_OSC evaluated successfully for all CPUs\n");
> >>          } else {
> >> --
> >> 2.43.0
> >>
>