linux-kernel - Re: [PATCH v3 4/5] cpufreq: arm_big

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Date:   Fri, 1 Feb 2019 11:53:57 +0000
From:   Sudeep Holla <sudeep.holla@....com>
To:     Quentin Perret <quentin.perret@....com>
Cc:     viresh.kumar@...aro.org, rjw@...ysocki.net, nm@...com,
        sboyd@...nel.org, mka@...omium.org, linux-pm@...r.kernel.org,
        Sudeep Holla <sudeep.holla@....com>,
        linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        dietmar.eggemann@....com
Subject: Re: [PATCH v3 4/5] cpufreq: arm_big_little: Register an Energy Model

On Fri, Feb 01, 2019 at 09:31:00AM +0000, Quentin Perret wrote:
> From: Dietmar Eggemann <dietmar.eggemann@....com>
>
> Now that PM_OPP provides a helper function to estimate the power
> consumed by CPUs, make sure to try and register an Energy Model (EM)
> from the arm_big_little CPUFreq driver, hence ensuring interested
> subsystems (the task scheduler, for example) can make use of that
> information when available.
>
> Signed-off-by: Dietmar Eggemann <dietmar.eggemann@....com>
> Signed-off-by: Quentin Perret <quentin.perret@....com>
> ---
>  drivers/cpufreq/arm_big_little.c | 8 ++++++++
>  1 file changed, 8 insertions(+)
>
> diff --git a/drivers/cpufreq/arm_big_little.c b/drivers/cpufreq/arm_big_little.c
> index cf62a1f64dd7..18b05bcb2614 100644
> --- a/drivers/cpufreq/arm_big_little.c
> +++ b/drivers/cpufreq/arm_big_little.c
> @@ -487,6 +487,14 @@ static int bL_cpufreq_init(struct cpufreq_policy *policy)
>  	policy->cpuinfo.transition_latency =
>  				arm_bL_ops->get_transition_latency(cpu_dev);
>
> +	ret = dev_pm_opp_get_opp_count(cpu_dev);
> +	if (ret <= 0) {
> +		dev_dbg(cpu_dev, "OPP table is not ready, deferring probe\n");
> +		return -EPROBE_DEFER;
> +	}

The only user of this has the check in init_opp_table that gets called from
get_cluster_clk_and_freq_table. So the above is not necessary, you can drop
it.

--
Regards,
Sudeep