lkml.org 
[lkml]   [2012]   [Jan]   [11]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
SubjectRe: [linux-pm] [RFC PATCH 1/2] thermal: Add a new trip type to use cooling device instance number
From
Hey Amit/Vincent,

It appears that with this implementation the STATE_ACTIVE trip number
used will also be the index of the cool_freq_tab used. If that is
true, then perhaps a common structure would be beneficial that links
each STATE_ACTIVE trip point with its corresponding cooling data.

BR,
Rob

On Tue, Dec 20, 2011 at 11:11 PM, Amit Kachhap <amit.kachhap@linaro.org> wrote:
>  Hi Vincent,
>
> Thanks for the review.
> Well actually your are correct that current temperature and last
> temperature can be used to increase or decrease the cpu frequency. But
> this has to be done again in cooling devices so to make the cooling
> devices generic and to avoid the temperature comparison again this new
> trip type passes the cooling device instance id.
> Also about your queries that this may add dependency between trip
> index and cooling state. This is actually needed and this dependency
> is created when the cooling device is binded with trip points(For
> cpufreq type cooling device just the instance of cooling device is
> associated with trip points). More over the existing PASSIVE cooling
> trip type does the same thing and iterates across all the cooling
> state.
>
>  Thanks,
>  Amit Daniel
>>
>> On 20 December 2011 18:07, Vincent Guittot <vincent.guittot@linaro.org> wrote:
>>>
>>> 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
>>
>>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at  http://www.tux.org/lkml/
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2012-01-11 09:15    [from the cache]
©2003-2011 Jasper Spaans