Re: [PATCH v4 2/2] thermal: add interface to support tune governor in run-time

[Zhang Rui <rui.zhang@intel.com>]

On Mon, 2014-01-20 at 17:55 +0800, Wei Ni wrote:
> In the of-thermal driver, it register a thermal zone device
> without governor,

I think this would be fixed by
https://patchwork.kernel.org/patch/3730411/
right?


>  since the governers are not static, we
> should be able to update to a new one in run-time, so I add
> a new fucntion thermal_update_governor() to do it.
> 
With the patch mentioned above, the of thermal zones will run with the
def_governor.
do we still need to switch to a different governor at runtime?

thanks,
rui

> Change-Id: Ie4995d6404d6d4f16250958487f3e3b8f63fc4c6
> Signed-off-by: Wei Ni <wni@nvidia.com>
> ---
>  Documentation/thermal/sysfs-api.txt |    4 ++++
>  drivers/thermal/thermal_core.c      |   38 ++++++++++++++++++++++++++++-------
>  include/linux/thermal.h             |    1 +
>  3 files changed, 36 insertions(+), 7 deletions(-)
> 
> diff --git a/Documentation/thermal/sysfs-api.txt b/Documentation/thermal/sysfs-api.txt
> index 8459d45..bcd50b5 100644
> --- a/Documentation/thermal/sysfs-api.txt
> +++ b/Documentation/thermal/sysfs-api.txt
> @@ -405,3 +405,7 @@ platform data is provided, this uses the step_wise throttling policy.
>  This function serves as an arbitrator to set the state of a cooling
>  device. It sets the cooling device to the deepest cooling state if
>  possible.
> +
> +5.5:thermal_update_governor:
> +This function update the thermal zone's governor to a new one.
> +Returns 0 if success, an erro code otherwise.
> diff --git a/drivers/thermal/thermal_core.c b/drivers/thermal/thermal_core.c
> index a91684b..ef0fc40 100644
> --- a/drivers/thermal/thermal_core.c
> +++ b/drivers/thermal/thermal_core.c
> @@ -130,6 +130,35 @@ exit:
>  	return;
>  }
>  
> +/**
> + * thermal_update_governor() - update the thermal zone device's governor
> + * to a new one.
> + * @tzd: pointer of thermal zone device, which need to update governor.
> + * @name: new governor name.
> + *
> + * Return: On success returns 0, an error code otherwise
> + */
> +int thermal_update_governor(struct thermal_zone_device *tzd,
> +			    const char *name)
> +{
> +	struct thermal_governor *new_gov;
> +	int ret = 0;
> +
> +	mutex_lock(&thermal_governor_lock);
> +
> +	new_gov = __find_governor(name);
> +	if (!new_gov) {
> +		ret = -EINVAL;
> +		goto exit;
> +	}
> +
> +	tzd->governor = new_gov;
> +
> +exit:
> +	mutex_unlock(&thermal_governor_lock);
> +	return ret;
> +}
> +
>  static int get_idr(struct idr *idr, struct mutex *lock, int *id)
>  {
>  	int ret;
> @@ -734,22 +763,17 @@ policy_store(struct device *dev, struct device_attribute *attr,
>  {
>  	int ret = -EINVAL;
>  	struct thermal_zone_device *tz = to_thermal_zone(dev);
> -	struct thermal_governor *gov;
>  	char name[THERMAL_NAME_LENGTH];
>  
>  	snprintf(name, sizeof(name), "%s", buf);
>  
> -	mutex_lock(&thermal_governor_lock);
> -
> -	gov = __find_governor(strim(name));
> -	if (!gov)
> +	ret = thermal_update_governor(tz, strim(name));
> +	if (ret < 0)
>  		goto exit;
>  
> -	tz->governor = gov;
>  	ret = count;
>  
>  exit:
> -	mutex_unlock(&thermal_governor_lock);
>  	return ret;
>  }
>  
> diff --git a/include/linux/thermal.h b/include/linux/thermal.h
> index f7e11c7..715b3cd 100644
> --- a/include/linux/thermal.h
> +++ b/include/linux/thermal.h
> @@ -293,6 +293,7 @@ struct thermal_instance *get_thermal_instance(struct thermal_zone_device *,
>  		struct thermal_cooling_device *, int);
>  void thermal_cdev_update(struct thermal_cooling_device *);
>  void thermal_notify_framework(struct thermal_zone_device *, int);
> +int thermal_update_governor(struct thermal_zone_device *, const char *);
>  
>  #ifdef CONFIG_NET
>  extern int thermal_generate_netlink_event(struct thermal_zone_device *tz,