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SubjectRe: [linux-pm] [RFC PATCH 1/2] thermal: Add a new trip type to use cooling device instance number
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Hi Amit,

I'm not sure that using the trip index for setting the state of a
cooling device is a generic solution because you are adding a
dependency between the trip index and the cooling device state that
might be difficult to handle. This dependency implies that a cooling
device like cpufreq_cooling_device must be registered in the 1st trips
of a thermal_zone which is not possible when we want to register 2
cpufreq_cooling_devices in the same thermal_zone.
You should only rely on the current and last temperatures to detect if
a trip_temp has been crossed and you should increase or decrease the
current state of the cooling device accordingly.

something like below should work with cpufreq_cooling_device and will
not add any constraint on the trip index. The state of a cooling
device is increased/decreased once for each trip

+ case THERMAL_TRIP_STATE_ACTIVE:
+ list_for_each_entry(instance, &tz->cooling_devices,
+ node) {
+ if (instance->trip != count)
+ continue;
+
+ cdev = instance->cdev;
+
+ if ((temp >= trip_temp)
+ && (trip_temp > tz->last_temperature)) {
+ cdev->ops->get_max_state(cdev,
+ &max_state);
+ cdev->ops->get_cur_state(cdev,
+ &current_state);
+ if (++current_state <= max_state)
+ cdev->ops->set_cur_state(cdev,
+ current_state);
+ }
+ else if ((temp < trip_temp)
+ && (trip_temp <= tz->last_temperature)) {
+ cdev->ops->get_cur_state(cdev,
+ &current_state);
+ if (current_state > 0)
+ cdev->ops->set_cur_state(cdev,
+ --current_state);
+ }
+ break;

Regards,
Vincent

On 13 December 2011 16:13, Amit Daniel Kachhap <amit.kachhap@linaro.org> wrote:
> This patch adds a new trip type THERMAL_TRIP_STATE_ACTIVE. This
> trip behaves same as THERMAL_TRIP_ACTIVE but also passes the cooling
> device instance number. This helps the cooling device registered as
> different instances to perform appropriate cooling action decision in
> the set_cur_state call back function.
>
> Also since the trip temperature's are in ascending order so some logic
> is put in place to skip the un-necessary checks.
>
> Signed-off-by: Amit Daniel Kachhap <amit.kachhap@linaro.org>
> ---
>  Documentation/thermal/sysfs-api.txt |    4 ++--
>  drivers/thermal/thermal_sys.c       |   27 ++++++++++++++++++++++++++-
>  include/linux/thermal.h             |    1 +
>  3 files changed, 29 insertions(+), 3 deletions(-)
>
> diff --git a/Documentation/thermal/sysfs-api.txt b/Documentation/thermal/sysfs-api.txt
> index b61e46f..5c1d44e 100644
> --- a/Documentation/thermal/sysfs-api.txt
> +++ b/Documentation/thermal/sysfs-api.txt
> @@ -184,8 +184,8 @@ trip_point_[0-*]_temp
>
>  trip_point_[0-*]_type
>        Strings which indicate the type of the trip point.
> -       E.g. it can be one of critical, hot, passive, active[0-*] for ACPI
> -       thermal zone.
> +       E.g. it can be one of critical, hot, passive, active[0-1],
> +       state-active[0-*] for ACPI thermal zone.
>        RO, Optional
>
>  cdev[0-*]
> diff --git a/drivers/thermal/thermal_sys.c b/drivers/thermal/thermal_sys.c
> index dd9a574..72b1ab3 100644
> --- a/drivers/thermal/thermal_sys.c
> +++ b/drivers/thermal/thermal_sys.c
> @@ -192,6 +192,8 @@ trip_point_type_show(struct device *dev, struct device_attribute *attr,
>                return sprintf(buf, "passive\n");
>        case THERMAL_TRIP_ACTIVE:
>                return sprintf(buf, "active\n");
> +       case THERMAL_TRIP_STATE_ACTIVE:
> +               return sprintf(buf, "state-active\n");
>        default:
>                return sprintf(buf, "unknown\n");
>        }
> @@ -1035,7 +1037,7 @@ EXPORT_SYMBOL(thermal_cooling_device_unregister);
>  void thermal_zone_device_update(struct thermal_zone_device *tz)
>  {
>        int count, ret = 0;
> -       long temp, trip_temp;
> +       long temp, trip_temp, max_state, last_trip_change = 0;
>        enum thermal_trip_type trip_type;
>        struct thermal_cooling_device_instance *instance;
>        struct thermal_cooling_device *cdev;
> @@ -1086,6 +1088,29 @@ void thermal_zone_device_update(struct thermal_zone_device *tz)
>                                        cdev->ops->set_cur_state(cdev, 0);
>                        }
>                        break;
> +               case THERMAL_TRIP_STATE_ACTIVE:
> +                       list_for_each_entry(instance, &tz->cooling_devices,
> +                                           node) {
> +                               if (instance->trip != count)
> +                                       continue;
> +
> +                               if (temp <= last_trip_change)
> +                                       continue;
> +
> +                               cdev = instance->cdev;
> +                               cdev->ops->get_max_state(cdev, &max_state);
> +
> +                               if ((temp >= trip_temp) &&
> +                                               ((count + 1) <= max_state))
> +                                       cdev->ops->set_cur_state(cdev,
> +                                                               count + 1);
> +                               else if ((temp < trip_temp) &&
> +                                                       (count <= max_state))
> +                                       cdev->ops->set_cur_state(cdev, count);
> +
> +                               last_trip_change = trip_temp;
> +                       }
> +                       break;
>                case THERMAL_TRIP_PASSIVE:
>                        if (temp >= trip_temp || tz->passive)
>                                thermal_zone_device_passive(tz, temp,
> diff --git a/include/linux/thermal.h b/include/linux/thermal.h
> index 47b4a27..d7d0a27 100644
> --- a/include/linux/thermal.h
> +++ b/include/linux/thermal.h
> @@ -42,6 +42,7 @@ enum thermal_trip_type {
>        THERMAL_TRIP_PASSIVE,
>        THERMAL_TRIP_HOT,
>        THERMAL_TRIP_CRITICAL,
> +       THERMAL_TRIP_STATE_ACTIVE,
>  };
>
>  struct thermal_zone_device_ops {
> --
> 1.7.1
>
> _______________________________________________
> linux-pm mailing list
> linux-pm@lists.linux-foundation.org
> https://lists.linuxfoundation.org/mailman/listinfo/linux-pm
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