[PATCH] cpufreq: intel_pstate: Fix active mode setting from command line

[PATCH] cpufreq: intel_pstate: Fix active mode setting from command line

[Rafael J. Wysocki]

From: Rafael J. Wysocki <rafael.j.wysocki@intel.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@telus.net>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
 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;

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

[Doug Smythies]

Hi Rafael,

Thank you.

On 2020.07.13 06:59 Rafael J. Wysocki wrote:
> 
> From: Rafael J. Wysocki <rafael.j.wysocki@intel.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@telus.net>
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Acked-by: Doug Smythies <dsmythies@telus.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;
>