linux-kernel - Re: [PATCH v2 3/7] ACPI: processor: idle: Relocate and verify acpi_processor_ffh_lpi

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Message-ID: <0029f2b2-4a52-4fd4-a76c-1032868ffbb0@huawei.com>
Date: Tue, 4 Nov 2025 17:37:56 +0800
From: "lihuisong (C)" <lihuisong@...wei.com>
To: "Rafael J. Wysocki" <rafael@...nel.org>
CC: <lenb@...nel.org>, <linux-acpi@...r.kernel.org>,
	<linux-kernel@...r.kernel.org>, <Sudeep.Holla@....com>,
	<linuxarm@...wei.com>, <jonathan.cameron@...wei.com>,
	<zhanjie9@...ilicon.com>, <zhenglifeng1@...wei.com>, <yubowen8@...wei.com>
Subject: Re: [PATCH v2 3/7] ACPI: processor: idle: Relocate and verify
 acpi_processor_ffh_lpi_probe


在 2025/11/4 1:56, Rafael J. Wysocki 写道:
> On Mon, Nov 3, 2025 at 9:42 AM Huisong Li <lihuisong@...wei.com> wrote:
>> The platform used LPI need check if the LPI support and the entry
>> method is valid by the acpi_processor_ffh_lpi_probe(). But the return
>> of acpi_processor_ffh_lpi_probe() in acpi_processor_setup_cpuidle_dev()
>> isn't verified by any caller.
>>
>> What's more, acpi_processor_get_power_info() is a more logical place for
>> verifying the validity of FFH LPI than acpi_processor_setup_cpuidle_dev().
>> So move acpi_processor_ffh_lpi_probe() from the latter to the former and
>> verify its return.
>>
>> Fixes: a36a7fecfe60 ("ACPI / processor_idle: Add support for Low Power Idle(LPI) states")
> If you want to add this Fixes: tag, please add some information on
> what systems it breaks on and what the symptoms are to the changelog.
Sorry, I didn't specifically construct it.
This patch is just an optimization patch. All right, I will drop this 
Fixes tag.
Thanks for your reminder.
>
>> Signed-off-by: Huisong Li <lihuisong@...wei.com>
>> ---
>>   drivers/acpi/processor_idle.c | 10 ++++++++--
>>   1 file changed, 8 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
>> index 5213a545fa78..c73df5933691 100644
>> --- a/drivers/acpi/processor_idle.c
>> +++ b/drivers/acpi/processor_idle.c
>> @@ -1266,7 +1266,7 @@ static int acpi_processor_setup_cpuidle_dev(struct acpi_processor *pr,
>>
>>          dev->cpu = pr->id;
>>          if (pr->flags.has_lpi)
>> -               return acpi_processor_ffh_lpi_probe(pr->id);
>> +               return 0;
>>
>>          return acpi_processor_setup_cpuidle_cx(pr, dev);
>>   }
>> @@ -1277,7 +1277,13 @@ static int acpi_processor_get_power_info(struct acpi_processor *pr)
>>
>>          ret = acpi_processor_get_lpi_info(pr);
>>          if (ret)
>> -               ret = acpi_processor_get_cstate_info(pr);
>> +               return acpi_processor_get_cstate_info(pr);
>> +
>> +       if (pr->flags.has_lpi) {
>> +               ret = acpi_processor_ffh_lpi_probe(pr->id);
>> +               if (ret)
>> +                       pr_err("Processor FFH LPI state is invalid.\n");
>> +       }
>>
>>          return ret;
>>   }
>> --