Re: [RFC PATCH 5/5] ACPI: processor: do update when maximum cooling state changed

From: Daniel Lezcano <daniel.lezcano@linaro.org>
To: Zhang Rui <rui.zhang@intel.com>, linux-pm@vger.kernel.org
Cc: tiwai@suse.de, viresh.kumar@linaro.org
Subject: Re: [RFC PATCH 5/5] ACPI: processor: do update when maximum cooling state changed
Date: Thu, 9 Apr 2020 15:34:56 +0200	[thread overview]
Message-ID: <5cd80df7-775e-96bd-cec5-b14965de2a67@linaro.org> (raw)
In-Reply-To: <20200408041917.2329-5-rui.zhang@intel.com>

Hi Rui,

On 08/04/2020 06:19, Zhang Rui wrote:
> ACPI processor cooling device supports 1 cooling state before cpufreq
> driver probed, and 4 cooling states after cpufreq driver probed.

What is this one state ?

> Thus update the statistics table when the cpufeq driver is
> probed/unprobed.

To be honest, the series seems to skirt a problem in the acpi processor.

If there is a new policy, then there is a new cooling device. Why not
unregister the old one and register the new one ?

> This fixes an OOB issue when updating the statistics of the processor
> cooling device.
> 
> Fixes: 8ea229511e06 ("thermal: Add cooling device's statistics in sysfs")
> Reported-by: Takashi Iwai <tiwai@suse.de>
> Signed-off-by: Zhang Rui <rui.zhang@intel.com>
> ---
>  drivers/acpi/processor_thermal.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/acpi/processor_thermal.c b/drivers/acpi/processor_thermal.c
> index 41feb88ee92d..179d1b50ee2b 100644
> --- a/drivers/acpi/processor_thermal.c
> +++ b/drivers/acpi/processor_thermal.c
> @@ -142,6 +142,7 @@ void acpi_thermal_cpufreq_init(struct cpufreq_policy *policy)
>  		if (ret < 0)
>  			pr_err("Failed to add freq constraint for CPU%d (%d)\n",
>  			       cpu, ret);
> +		thermal_cdev_stats_update_max(pr->cdev);
>  	}
>  }
>  
> @@ -154,6 +155,7 @@ void acpi_thermal_cpufreq_exit(struct cpufreq_policy *policy)
>  
>  		if (pr)
>  			freq_qos_remove_request(&pr->thermal_req);
> +		thermal_cdev_stats_update_max(pr->cdev);
>  	}
>  }
>  #else				/* ! CONFIG_CPU_FREQ */
> 

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