linux-kernel - Re: [PATCH v5 0/8] Support for autonomous selection in cppc

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Message-ID: <ddbc0336-9083-4054-8930-c22bd8337488@huawei.com>
Date: Sat, 22 Feb 2025 18:07:44 +0800
From: "zhenglifeng (A)" <zhenglifeng1@...wei.com>
To: "Rafael J. Wysocki" <rafael@...nel.org>
CC: <lenb@...nel.org>, <robert.moore@...el.com>, <viresh.kumar@...aro.org>,
	<mario.limonciello@....com>, <gautham.shenoy@....com>, <ray.huang@....com>,
	<pierre.gondois@....com>, <acpica-devel@...ts.linux.dev>,
	<linux-acpi@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
	<linux-pm@...r.kernel.org>, <linuxarm@...wei.com>, <yumpusamongus@...il.com>,
	<srinivas.pandruvada@...ux.intel.com>, <jonathan.cameron@...wei.com>,
	<zhanjie9@...ilicon.com>, <lihuisong@...wei.com>, <hepeng68@...wei.com>,
	<fanghao11@...wei.com>
Subject: Re: [PATCH v5 0/8] Support for autonomous selection in cppc_cpufreq

On 2025/2/19 3:17, Rafael J. Wysocki wrote:
> On Thu, Feb 13, 2025 at 2:55 AM zhenglifeng (A) <zhenglifeng1@...wei.com> wrote:
>>
>> On 2025/2/6 21:14, Lifeng Zheng wrote:
>>> Add sysfs interfaces for CPPC autonomous selection in the cppc_cpufreq
>>> driver.
>>>
>>> The patch series is organized in two parts:
>>>
>>>  - patch 1-5 refactor out the general CPPC register get and set functions
>>>    in cppc_acpi.c
>>>
>>>  - patches 6-8 expose sysfs files for users to control CPPC autonomous
>>>    selection when supported
>>>
>>> Changelog:
>>>
>>> v5:
>>>
>>>  - add more explanation to the commit logs and comments
>>>  - change REG_OPTIONAL from bin to hex
>>>  - split patch 2 into 3 smaller patches
>>>  - remove CPPC_REG_VAL_READ() and CPPC_REG_VAL_WRITE() macros
>>>  - move the modification part in patch 5 into a separate patch
>>>  - rename the sysfs file from "energy_perf" to
>>>    energy_performance_preference_val
>>>
>>> v4:
>>>
>>>  - add REG_OPTIONAL and IS_OPTIONAL_CPC_REG to judge if a cpc register is
>>>    an optional one
>>>  - check whether the register is optional before CPC_SUPPORTED check in
>>>    cppc_get_reg_val() and cppc_set_reg_val()
>>>  - check the register's type in cppc_set_reg_val()
>>>  - add macros to generally implement registers getting and setting
>>>    functions
>>>  - move some logic codes from cppc_cpufreq.c to cppc_acpi.c
>>>  - replace cppc_get_auto_sel_caps() by cppc_get_auto_sel()
>>>
>>> v3:
>>>
>>>  - change cppc_get_reg() and cppc_set_reg() name to cppc_get_reg_val() and
>>>    cppc_set_reg_val()
>>>  - extract cppc_get_reg_val_in_pcc() and cppc_set_reg_val_in_pcc()
>>>  - return the result of cpc_read() in cppc_get_reg_val()
>>>  - add pr_debug() in cppc_get_reg_val_in_pcc() when pcc_ss_id < 0
>>>  - rename 'cpunum' to 'cpu' in cppc_get_reg_val()
>>>  - move some macros from drivers/cpufreq/cppc_cpufreq.c to
>>>    include/acpi/cppc_acpi.h with a CPPC_XXX prefix
>>>
>>> v2:
>>>
>>>  - fix some incorrect placeholder
>>>  - change kstrtoul to kstrtobool in store_auto_select
>>>
>>> Lifeng Zheng (8):
>>>   ACPI: CPPC: Add IS_OPTIONAL_CPC_REG macro to judge if a cpc_reg is
>>>     optional
>>>   ACPI: CPPC: Optimize cppc_get_perf()
>>>   ACPI: CPPC: Rename cppc_get_perf() to cppc_get_reg_val()
>>>   ACPI: CPPC: Add cppc_set_reg_val()
>>>   ACPI: CPPC: Refactor register value get and set ABIs
>>>   ACPI: CPPC: Modify cppc_get_auto_sel_caps() to cppc_get_auto_sel()
>>>   ACPI: CPPC: Add three functions related to autonomous selection
>>>   cpufreq: CPPC: Support for autonomous selection in cppc_cpufreq
>>>
>>>  .../ABI/testing/sysfs-devices-system-cpu      |  54 ++++
>>>  drivers/acpi/cppc_acpi.c                      | 303 +++++++++++-------
>>>  drivers/cpufreq/amd-pstate.c                  |   3 +-
>>>  drivers/cpufreq/cppc_cpufreq.c                | 109 +++++++
>>>  include/acpi/cppc_acpi.h                      |  30 +-
>>>  5 files changed, 372 insertions(+), 127 deletions(-)
>>>
>>
>> Gentle ping.
> 
> OK, so I'm wondering how this is related to the patch series at
> 
> https://lore.kernel.org/linux-acpi/20250211103737.447704-1-sumitg@nvidia.com/

This series refactors some cppc_acpi ABIs and supports cppc autonomous
selection with sysfs files in cpufreq policy.  Later, [1] proposed another
design with different user interfaces.We will discuss and reach a consensus
with regard to this.

However, as mentioned in [1], patch 1-7 in this series (the cppc_acpi part)
are not related to user interfaces, so can be reviewed and applied
separately.  I can also send patch 1-7 as a new thread if preferred.

[1] https://lore.kernel.org/linux-acpi/20250211103737.447704-1-sumitg@nvidia.com/

> 
>> Attach discussions of previous versions:
>> v1: https://lore.kernel.org/all/20241114084816.1128647-1-zhenglifeng1@huawei.com/
>> v2: https://lore.kernel.org/all/20241122062051.3658577-1-zhenglifeng1@huawei.com/
>> v3: https://lore.kernel.org/all/20241216091603.1247644-1-zhenglifeng1@huawei.com/
>> v4: https://lore.kernel.org/all/20250113122104.3870673-1-zhenglifeng1@huawei.com/
>>
>