linux-kernel - RE: [PATCH 07/14] cpufreq: intel_pstate: Skip unnecessary PID resets on init

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Date:   Tue, 14 Mar 2017 09:06:52 -0700
From:   "Doug Smythies" <dsmythies@...us.net>
To:     "'Rafael J. Wysocki'" <rjw@...ysocki.net>
Cc:     "'LKML'" <linux-kernel@...r.kernel.org>,
        "'Srinivas Pandruvada'" <srinivas.pandruvada@...ux.intel.com>,
        "'Linux PM'" <linux-pm@...r.kernel.org>
Subject: RE: [PATCH 07/14] cpufreq: intel_pstate: Skip unnecessary PID resets on init

On 2017.03.12 10:19 Rafael J. Wysocki wrote:

> From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
>
> PID controller parameters only need to be initialized if the
> get_target_pstate_use_performance() P-state selection routine
> is going to be used.  It is not necessary to initialize them
> otherwise, so don't do that.
>
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
> ---
> drivers/cpufreq/intel_pstate.c |    4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> Index: linux-pm/drivers/cpufreq/intel_pstate.c
> ===================================================================
> --- linux-pm.orig/drivers/cpufreq/intel_pstate.c
> +++ linux-pm/drivers/cpufreq/intel_pstate.c
> @@ -1974,12 +1974,12 @@ static int intel_pstate_init_cpu(unsigne
> 			intel_pstate_disable_ee(cpunum);
> 
>  		intel_pstate_hwp_enable(cpu);
> +	} else if (pstate_funcs.get_target_pstate == get_target_pstate_use_performance) {
> +		intel_pstate_pid_reset(cpu);
>  	}
> 
>  	intel_pstate_get_cpu_pstates(cpu);
> 
> -	intel_pstate_pid_reset(cpu);
> -
>  	pr_debug("controlling: cpu %d\n", cpunum);
> 
> 	return 0;

Hi Rafael,

The patch has a long line and scripts/checkpatch.pl complains.

$ scripts/checkpatch.pl rjw_7_14.txt
WARNING: line over 80 characters
#27: FILE: drivers/cpufreq/intel_pstate.c:1977:
+       } else if (pstate_funcs.get_target_pstate == get_target_pstate_use_performance) {

total: 0 errors, 1 warnings, 14 lines checked

Myself, I don't care, and only found this by accident. I am just passing along
the information.

... Doug