linux-kernel - Re: [PATCHv4 1/1] thermal: core: call thermal_zone_device

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Message-ID: <20160623045158.GB3379@f23x64.localdomain>
Date:	Wed, 22 Jun 2016 21:51:58 -0700
From:	Darren Hart <dvhart@...radead.org>
To:	Eduardo Valentin <edubezval@...il.com>
Cc:	Rui Zhang <rui.zhang@...el.com>,
	"Rafael J. Wysocki" <rjw@...ysocki.net>,
	Len Brown <lenb@...nel.org>, linux-acpi@...r.kernel.org,
	"Lee, Chun-Yi" <jlee@...e.com>, Keerthy <j-keerthy@...com>,
	linux-kernel@...r.kernel.org, linux-omap@...r.kernel.org,
	platform-driver-x86@...r.kernel.org, linux-pm@...r.kernel.org,
	Peter Feuerer <peter@...e.net>
Subject: Re: [PATCHv4 1/1] thermal: core: call thermal_zone_device_update()
 after mode update

On Wed, Jun 22, 2016 at 08:03:18AM -0700, Eduardo Valentin wrote:
> Because several drivers do the following pattern:
> .set_mode()
>    ...
>    local_data->mode = new_mode;
>    thermal_zone_device_update(tz);
> 
> makes sense to simply do the thermal_zone_device_update()
> in thermal core, after setting the new mode.
> 
> Also, this patch also remove deadlocks on drivers that
> call thermal_zone_device_update() on .set_mode(),
> as .set_mode()  is now called always with tz->lock held.
> 
> Cc: "Rafael J. Wysocki" <rjw@...ysocki.net>
> Cc: Len Brown <lenb@...nel.org>
> Cc: linux-acpi@...r.kernel.org
> Cc: "Lee, Chun-Yi" <jlee@...e.com>
> Cc: Darren Hart <dvhart@...radead.org>
> Cc: Zhang Rui <rui.zhang@...el.com>
> Cc: Keerthy <j-keerthy@...com>
> Cc: linux-kernel@...r.kernel.org
> Cc: linux-omap@...r.kernel.org
> Cc: platform-driver-x86@...r.kernel.org
> Cc: linux-pm@...r.kernel.org
> Signed-off-by: Eduardo Valentin <edubezval@...il.com>

+Peter Feuerer <peter@...e.net>

Peter, any concerns regarding the acerhdf driver?

> ---
> Hello,
> 
> V3->V4:
> - ti-soc: Removed extra locking from TI SoC in set_mode
> - ACPI: Kept the update on check as it is called on other places
> 
> BR,
> 
> Eduardo
> 
>  drivers/acpi/thermal.c                             | 1 -
>  drivers/platform/x86/acerhdf.c                     | 1 -
>  drivers/thermal/imx_thermal.c                      | 1 -
>  drivers/thermal/of-thermal.c                       | 5 -----
>  drivers/thermal/thermal_sysfs.c                    | 1 +
>  drivers/thermal/ti-soc-thermal/ti-thermal-common.c | 5 -----
>  6 files changed, 1 insertion(+), 13 deletions(-)
> 
> diff --git a/drivers/acpi/thermal.c b/drivers/acpi/thermal.c
> index 82707f9..03c3460 100644
> --- a/drivers/acpi/thermal.c
> +++ b/drivers/acpi/thermal.c
> @@ -581,7 +581,6 @@ static int thermal_set_mode(struct thermal_zone_device *thermal,
>  		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
>  			"%s kernel ACPI thermal control\n",
>  			tz->tz_enabled ? "Enable" : "Disable"));
> -		acpi_thermal_check(tz);
>  	}
>  	return 0;
>  }
> diff --git a/drivers/platform/x86/acerhdf.c b/drivers/platform/x86/acerhdf.c
> index 460fa67..aee33ba 100644
> --- a/drivers/platform/x86/acerhdf.c
> +++ b/drivers/platform/x86/acerhdf.c
> @@ -405,7 +405,6 @@ static inline void acerhdf_enable_kernelmode(void)
>  	kernelmode = 1;
>  
>  	thz_dev->polling_delay = interval*1000;
> -	thermal_zone_device_update(thz_dev);
>  	pr_notice("kernel mode fan control ON\n");
>  }
>  
> diff --git a/drivers/thermal/imx_thermal.c b/drivers/thermal/imx_thermal.c
> index c5547bd..a413eb6 100644
> --- a/drivers/thermal/imx_thermal.c
> +++ b/drivers/thermal/imx_thermal.c
> @@ -246,7 +246,6 @@ static int imx_set_mode(struct thermal_zone_device *tz,
>  	}
>  
>  	data->mode = mode;
> -	thermal_zone_device_update(tz);
>  
>  	return 0;
>  }
> diff --git a/drivers/thermal/of-thermal.c b/drivers/thermal/of-thermal.c
> index b8e509c..95c47da 100644
> --- a/drivers/thermal/of-thermal.c
> +++ b/drivers/thermal/of-thermal.c
> @@ -282,17 +282,12 @@ static int of_thermal_set_mode(struct thermal_zone_device *tz,
>  {
>  	struct __thermal_zone *data = tz->devdata;
>  
> -	mutex_lock(&tz->lock);
> -
>  	if (mode == THERMAL_DEVICE_ENABLED)
>  		tz->polling_delay = data->polling_delay;
>  	else
>  		tz->polling_delay = 0;
>  
> -	mutex_unlock(&tz->lock);
> -
>  	data->mode = mode;
> -	thermal_zone_device_update(tz);
>  
>  	return 0;
>  }
> diff --git a/drivers/thermal/thermal_sysfs.c b/drivers/thermal/thermal_sysfs.c
> index 743df50..3d0dc30 100644
> --- a/drivers/thermal/thermal_sysfs.c
> +++ b/drivers/thermal/thermal_sysfs.c
> @@ -100,6 +100,7 @@ mode_store(struct device *dev, struct device_attribute *attr,
>  	mutex_lock(&tz->lock);
>  	result = tz->ops->set_mode(tz, mode);
>  	mutex_unlock(&tz->lock);
> +	thermal_zone_device_update(tz);
>  
>  	if (result)
>  		return result;
> diff --git a/drivers/thermal/ti-soc-thermal/ti-thermal-common.c b/drivers/thermal/ti-soc-thermal/ti-thermal-common.c
> index 15c0a9a..5dce053 100644
> --- a/drivers/thermal/ti-soc-thermal/ti-thermal-common.c
> +++ b/drivers/thermal/ti-soc-thermal/ti-thermal-common.c
> @@ -193,19 +193,14 @@ static int ti_thermal_set_mode(struct thermal_zone_device *thermal,
>  		return 0;
>  	}
>  
> -	mutex_lock(&data->ti_thermal->lock);
> -
>  	if (mode == THERMAL_DEVICE_ENABLED)
>  		data->ti_thermal->polling_delay = FAST_TEMP_MONITORING_RATE;
>  	else
>  		data->ti_thermal->polling_delay = 0;
>  
> -	mutex_unlock(&data->ti_thermal->lock);
> -
>  	data->mode = mode;
>  	ti_bandgap_write_update_interval(bgp, data->sensor_id,
>  					data->ti_thermal->polling_delay);
> -	thermal_zone_device_update(data->ti_thermal);
>  	dev_dbg(&thermal->device, "thermal polling set for duration=%d msec\n",
>  		data->ti_thermal->polling_delay);
>  
> -- 
> 2.1.4
> 
> 

-- 
Darren Hart
Intel Open Source Technology Center