linux-kernel - Re: [PATCH v2 1/4] ACPI: CPPC: Add a symbol to check if the preferred profile is a server

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Message-ID: <45a43152-fdf1-5f1e-1a46-0d9798c4090b@amd.com>
Date:   Tue, 20 Jun 2023 09:56:18 -0500
From:   "Limonciello, Mario" <mario.limonciello@....com>
To:     Huang Rui <ray.huang@....com>, "Yuan, Perry" <Perry.Yuan@....com>
Cc:     "rafael.j.wysocki@...el.com" <rafael.j.wysocki@...el.com>,
        "viresh.kumar@...aro.org" <viresh.kumar@...aro.org>,
        "Sharma, Deepak" <Deepak.Sharma@....com>,
        "Karny, Wyes" <Wyes.Karny@....com>,
        "Shenoy, Gautham Ranjal" <gautham.shenoy@....com>,
        "Li, Sun peng (Leo)" <Sunpeng.Li@....com>,
        "Huang, Shimmer" <Shimmer.Huang@....com>,
        "Du, Xiaojian" <Xiaojian.Du@....com>,
        "Meng, Li (Jassmine)" <Li.Meng@....com>,
        "linux-pm@...r.kernel.org" <linux-pm@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2 1/4] ACPI: CPPC: Add a symbol to check if the preferred
 profile is a server


On 6/20/2023 9:50 AM, Huang Rui wrote:
> On Thu, Jun 15, 2023 at 02:32:00PM +0800, Yuan, Perry wrote:
>> From: Mario Limonciello <mario.limonciello@....com>
>>
>> This symbol will be used by intel-pstate and amd-pstate for making
>> decisions based on what the FADT indicates the system pm profile is.
>>
>> Suggested-by: Gautham Ranjal Shenoy <gautham.shenoy@....com>
>> Link: https://uefi.org/htmlspecs/ACPI_Spec_6_4_html/05_ACPI_Software_Programming_Model/ACPI_Software_Programming_Model.html#fixed-acpi-description-table-fadt
>> Signed-off-by: Mario Limonciello <mario.limonciello@....com>
>> ---
>>   drivers/acpi/cppc_acpi.c | 34 ++++++++++++++++++++++++++++++++++
>>   include/acpi/actbl.h     |  3 ++-
>>   include/acpi/processor.h | 10 ++++++++++
>>   3 files changed, 46 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c
>> index 7ff269a78c20..d8827eae3ba4 100644
>> --- a/drivers/acpi/cppc_acpi.c
>> +++ b/drivers/acpi/cppc_acpi.c
>> @@ -941,6 +941,40 @@ void acpi_cppc_processor_exit(struct acpi_processor *pr)
>>   }
>>   EXPORT_SYMBOL_GPL(acpi_cppc_processor_exit);
>>   
>> +
>> +/**
>> + * acpi_pm_profile_server() - Check if the system is a server.
>> + *
>> + * Return: true for server profiles, false for anything else
>> + */
>> +bool acpi_pm_profile_server(void)
>> +{
>> +	switch (acpi_gbl_FADT.preferred_profile) {
>> +	case PM_ENTERPRISE_SERVER:
>> +	case PM_SOHO_SERVER:
>> +	case PM_PERFORMANCE_SERVER:
>> +		return true;
>> +	}
>> +	return false;
>> +}
>> +EXPORT_SYMBOL_GPL(acpi_pm_profile_server);
>> +
>> +/**
>> + * acpi_pm_profile_undefined() - Check if the system is an undefined pm profile.
>> + *
>> + * Return: true for undefined profiles, false for anything else
>> + */
>> +bool acpi_pm_profile_undefined(void)
>> +{
>> +	if (acpi_gbl_FADT.preferred_profile == PM_UNSPECIFIED)
>> +		return true;
>> +	if (acpi_gbl_FADT.preferred_profile >= NR_PM_PROFILES)
>> +		return true;
> May I know the acpi_gbl_FADT.preferred_profile value of powerful desktop
> such as threadripper or AM4/AM5 socket types of processors?

I have a Threadripper for my workstation, and it's:

[02Dh 0045   1]                   PM Profile : 01 [Desktop]

> I am thinking whether we can use this way to differentiate powerful desktop
> and mobile platforms.

On a Rembrandt laptop it's:

[02Dh 0045   1]                   PM Profile : 02 [Mobile]

Given Raphael's comments about intel-pstate preferring not to
match "SOHO server" as a server, I am planning to move these functions
into amd-pstate directly and drop patch 4.
> Thanks,
> Ray
>
>> +	return false;
>> +}
>> +EXPORT_SYMBOL_GPL(acpi_pm_profile_undefined);
>> +
>> +
>>   /**
>>    * cpc_read_ffh() - Read FFH register
>>    * @cpunum:	CPU number to read
>> diff --git a/include/acpi/actbl.h b/include/acpi/actbl.h
>> index e5dfb6f4de52..451f6276da49 100644
>> --- a/include/acpi/actbl.h
>> +++ b/include/acpi/actbl.h
>> @@ -307,7 +307,8 @@ enum acpi_preferred_pm_profiles {
>>   	PM_SOHO_SERVER = 5,
>>   	PM_APPLIANCE_PC = 6,
>>   	PM_PERFORMANCE_SERVER = 7,
>> -	PM_TABLET = 8
>> +	PM_TABLET = 8,
>> +	NR_PM_PROFILES = 9
>>   };
>>   
>>   /* Values for sleep_status and sleep_control registers (V5+ FADT) */
>> diff --git a/include/acpi/processor.h b/include/acpi/processor.h
>> index 94181fe9780a..05a45ebddaea 100644
>> --- a/include/acpi/processor.h
>> +++ b/include/acpi/processor.h
>> @@ -360,6 +360,8 @@ int acpi_get_cpuid(acpi_handle, int type, u32 acpi_id);
>>   #ifdef CONFIG_ACPI_CPPC_LIB
>>   extern int acpi_cppc_processor_probe(struct acpi_processor *pr);
>>   extern void acpi_cppc_processor_exit(struct acpi_processor *pr);
>> +extern bool acpi_pm_profile_server(void);
>> +extern bool acpi_pm_profile_undefined(void);
>>   #else
>>   static inline int acpi_cppc_processor_probe(struct acpi_processor *pr)
>>   {
>> @@ -369,6 +371,14 @@ static inline void acpi_cppc_processor_exit(struct acpi_processor *pr)
>>   {
>>   	return;
>>   }
>> +static inline bool acpi_pm_profile_server(void)
>> +{
>> +	return false;
>> +}
>> +static inline bool acpi_pm_profile_undefined(void)
>> +{
>> +	return true;
>> +}
>>   #endif	/* CONFIG_ACPI_CPPC_LIB */
>>   
>>   /* in processor_pdc.c */
>> -- 
>> 2.34.1
>>