linux-kernel - Re: [PATCH] cpufreq: CPPC: Correct desired

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Message-ID: <20161012032153.GE19385@vireshk-i7>
Date:   Wed, 12 Oct 2016 08:51:53 +0530
From:   Viresh Kumar <viresh.kumar@...aro.org>
To:     Hoan Tran <hotran@....com>
Cc:     "Rafael J. Wysocki" <rjw@...ysocki.net>, pprakash@...eaurora.org,
        Al Stone <ahs3@...hat.com>, linux-pm@...r.kernel.org,
        linux-kernel@...r.kernel.org, lho@....com,
        Duc Dang <dhdang@....com>
Subject: Re: [PATCH] cpufreq: CPPC: Correct desired_perf calculation

On 11-10-16, 14:12, Hoan Tran wrote:
> The desired_perf is an abstract performance number. Its value should
> be in the range of [lowest perf, highest perf] of CPPC.
> The correct calculation is
>   desired_perf = freq * cppc_highest_perf / cppc_dmi_max_khz
> 
> Signed-off-by: Hoan Tran <hotran@....com>
> ---
>  drivers/cpufreq/cppc_cpufreq.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/cpufreq/cppc_cpufreq.c b/drivers/cpufreq/cppc_cpufreq.c
> index 1b2f28f..ab1d4b7 100644
> --- a/drivers/cpufreq/cppc_cpufreq.c
> +++ b/drivers/cpufreq/cppc_cpufreq.c
> @@ -84,7 +84,7 @@ static int cppc_cpufreq_set_target(struct cpufreq_policy *policy,
>  
>  	cpu = all_cpu_data[policy->cpu];
>  
> -	cpu->perf_ctrls.desired_perf = (u64)target_freq * policy->max / cppc_dmi_max_khz;
> +	cpu->perf_ctrls.desired_perf = (u64)target_freq * cpu->perf_caps.highest_perf / cppc_dmi_max_khz;
>  	freqs.old = policy->cur;
>  	freqs.new = target_freq;

I am not sure what the calculations should be like, but I don't have
any objections against applying this..

Acked-by: Viresh Kumar <viresh.kumar@...aro.org>

-- 
viresh