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

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Message-ID: <50fcefb1-e910-435d-be0d-d0f45071d179@amd.com>
Date: Tue, 18 Jun 2024 14:33:05 -0500
From: Mario Limonciello <mario.limonciello@....com>
To: "Rafael J. Wysocki" <rafael@...nel.org>
Cc: "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 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?

> 
>> 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
>>