linux-kernel - Re: [PATCH] ACPI: update user_policy.max when

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Message-ID: <31897041.QcNuTieHbo@vostro.rjw.lan>
Date:	Wed, 05 Jun 2013 22:40:11 +0200
From:	"Rafael J. Wysocki" <rjw@...k.pl>
To:	Joe Jin <joe.jin@...cle.com>
Cc:	Viresh Kumar <viresh.kumar@...aro.org>,
	Neil Gu <qing.gu@...cle.com>, cpufreq@...r.kernel.org,
	linux-pm@...r.kernel.org,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] ACPI: update user_policy.max when _PPC updated

On Wednesday, June 05, 2013 08:52:52 AM Joe Jin wrote:
> When _PPC changed dynamically the user_policy.max will not be updated,
> this prevent CPU run on the highest frequency.

Why should the user setting be always related to the current maximum available
frequency?  What if the user sets the limit for power capping purposes?

Rafael


> Signed-off-by: Joe Jin <joe.jin@...cle.com>
> Cc: Rafael J. Wysocki <rjw@...k.pl>
> Cc: Viresh Kumar <viresh.kumar@...aro.org>
> ---
>  drivers/acpi/processor_perflib.c | 17 ++++++++++++++++-
>  1 file changed, 16 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/acpi/processor_perflib.c b/drivers/acpi/processor_perflib.c
> index e854582..e01aa7d 100644
> --- a/drivers/acpi/processor_perflib.c
> +++ b/drivers/acpi/processor_perflib.c
> @@ -180,6 +180,7 @@ static void acpi_processor_ppc_ost(acpi_handle handle, int status)
>  int acpi_processor_ppc_has_changed(struct acpi_processor *pr, int event_flag)
>  {
>  	int ret;
> +	unsigned int saved = (unsigned int)pr->performance_platform_limit;
>  
>  	if (ignore_ppc) {
>  		/*
> @@ -204,8 +205,22 @@ int acpi_processor_ppc_has_changed(struct acpi_processor *pr, int event_flag)
>  	}
>  	if (ret < 0)
>  		return (ret);
> -	else
> +	else {
> +		unsigned int ppc = (unsigned int)pr->performance_platform_limit;
> +
> +		if (saved != ppc) {
> +			struct cpufreq_policy *policy;
> +
> +			policy = cpufreq_cpu_get(pr->id);
> +			if (likely(policy))
> +				policy->user_policy.max =
> +					pr->performance->states[ppc].
> +					core_frequency * 1000;
> +			cpufreq_cpu_put(policy);
> +		}
> +
>  		return cpufreq_update_policy(pr->id);
> +	}
>  }
>  
>  int acpi_processor_get_bios_limit(int cpu, unsigned int *limit)
> 
-- 
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
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