linux-kernel - RE: [PATCH] cpufreq: intel_pstate: Fix active mode setting from command line

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Date:   Mon, 13 Jul 2020 08:24:27 -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] cpufreq: intel_pstate: Fix active mode setting from command line

Hi Rafael,

Thank you.

On 2020.07.13 06:59 Rafael J. Wysocki wrote:
> 
> From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
> 
> If intel_pstate starts in the passive mode by default (that happens
> when the processor in the system doesn't support HWP), passing
> intel_pstate=active in the kernel command line doesn't work, so
> fix that.
> 
> Fixes: 33aa46f252c7 ("cpufreq: intel_pstate: Use passive mode by default without HWP")
> Reported-by: Doug Smythies <dsmythies@...us.net>
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>

Acked-by: Doug Smythies <dsmythies@...us.net>

> ---
>  drivers/cpufreq/intel_pstate.c |    8 ++++++--
>  1 file changed, 6 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
> @@ -2534,7 +2534,7 @@ static struct cpufreq_driver intel_cpufr
>  	.name		= "intel_cpufreq",
>  };
> 
> -static struct cpufreq_driver *default_driver = &intel_pstate;
> +static struct cpufreq_driver *default_driver;
> 
>  static void intel_pstate_driver_cleanup(void)
>  {
> @@ -2828,6 +2828,7 @@ static int __init intel_pstate_init(void
>  			hwp_active++;
>  			hwp_mode_bdw = id->driver_data;
>  			intel_pstate.attr = hwp_cpufreq_attrs;
> +			default_driver = &intel_pstate;
>  			goto hwp_cpu_matched;
>  		}
>  	} else {
> @@ -2845,7 +2846,8 @@ static int __init intel_pstate_init(void
>  		return -ENODEV;
>  	}
>  	/* Without HWP start in the passive mode. */
> -	default_driver = &intel_cpufreq;
> +	if (!default_driver)
> +		default_driver = &intel_cpufreq;
> 
>  hwp_cpu_matched:
>  	/*
> @@ -2899,6 +2901,8 @@ static int __init intel_pstate_setup(cha
> 
>  	if (!strcmp(str, "disable")) {
>  		no_load = 1;
> +	} else if (!strcmp(str, "active")) {
> +		default_driver = &intel_pstate;
>  	} else if (!strcmp(str, "passive")) {
>  		default_driver = &intel_cpufreq;
>  		no_hwp = 1;
>