Re: [linux-pm] [PATCH 1/4] thermal: Add a new trip type to usecooling device instance number

From: Eduardo Valentin
Date: Tue Apr 03 2012 - 10:16:14 EST

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Hello,

On Thu, Feb 23, 2012 at 04:50:14PM +0530, Amit Kachhap wrote:
> On 23 February 2012 12:16, R, Durgadoss <durgadoss.r@xxxxxxxxx> wrote:
> > Hi Amit,
> >
> >> -----Original Message-----
> >> From: amit kachhap [mailto:amitdanielk@xxxxxxxxx] On Behalf Of Amit Daniel
> >> Kachhap
> >> Sent: Wednesday, February 22, 2012 3:44 PM
> >> To: linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx
> >> Cc: linux-kernel@xxxxxxxxxxxxxxx; mjg59@xxxxxxxxxxxxx; linux-
> >> acpi@xxxxxxxxxxxxxxx; lenb@xxxxxxxxxx; linaro-dev@xxxxxxxxxxxxxxxx;
> >> amit.kachhap@xxxxxxxxxx; R, Durgadoss; rob.lee@xxxxxxxxxx; patches@xxxxxxxxxx
> >> Subject: [PATCH 1/4] thermal: Add a new trip type to use cooling device
> >> instance number
> >>
> >> 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@xxxxxxxxxx>
> >> ---
> >> Documentation/thermal/sysfs-api.txt | 4 +-
> >> drivers/thermal/thermal_sys.c | 45 ++++++++++++++++++++++++++++++++--
> >> include/linux/thermal.h | 1 +
> >> 3 files changed, 45 insertions(+), 5 deletions(-)
> >>
> >> diff --git a/Documentation/thermal/sysfs-api.txt b/Documentation/thermal/sysfs-
> >> api.txt
> >> index 1733ab9..7a0c080 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 220ce7e..d4c9b20 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");
> >> }
> >> @@ -1034,10 +1036,10 @@ EXPORT_SYMBOL(thermal_cooling_device_unregister);
> >>
> >> void thermal_zone_device_update(struct thermal_zone_device *tz)
> >> {
> >> - int count, ret = 0;
> >> - long temp, trip_temp;
> >> + int count, ret = 0, inst_id;
> >> + 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_instance *instance, *state_instance;
> >> struct thermal_cooling_device *cdev;
> >>
> >> mutex_lock(&tz->lock);
> >> @@ -1086,6 +1088,43 @@ 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;
> >> +
> >> + inst_id = 0;
> >> + /*
> >> + *For this instance how many instance of same
> >> + *cooling device occured before
> >> + */
> >> +
> >> + list_for_each_entry(state_instance,
> >> + &tz->cooling_devices, node) {
> >> + if (instance->cdev ==
> >> + state_instance->cdev)
> >> + inst_id++;
> >> + if (state_instance->trip == count)
> >> + break;
> >> + }
> >
> > Can you explain a bit more on this loop and the set_cur_state below ?
> > Sorry, I don't get the logic behind this..
>
> This loop is basically finding the instance id of the same cooling device.
> Say we have done like this,
> thermal_zone_bind_cooling_device(thermal, 2, cdev);
> thermal_zone_bind_cooling_device(thermal, 3, cdev);
> thermal_zone_bind_cooling_device(thermal, 4, cdev);
>
> In above same cooling device cdev is binded to trip no 2,3 and 4 with
> inst_id generated as 1,2,3 respectively. so set_cur_state for those
> trip reached will be called as,
> set_cur_state(cdev, 1);
> set_cur_state(cdev, 2);
> set_cur_state(cdev, 3);

In this case, why a simple state = get_cur_state() followed by a
set_cur_state(++state) / set_cur_state(--state) is not enough?

Another thing is if we want to do jumps in the sequence?

set_cur_state(cdev, 1);
set_cur_state(cdev, 3);
set_cur_state(cdev, 6);

But for that we need a table mapping, trip vs. state.

What do you think?

>
> Thanks,
> Amit D
>
> >
> > Thanks,
> > Durga
> >
> >> +
> >> + cdev = instance->cdev;
> >> + cdev->ops->get_max_state(cdev, &max_state);
> >> +
> >> + if ((temp >= trip_temp) &&
> >> + (inst_id <= max_state))
> >> + cdev->ops->set_cur_state(cdev, inst_id);
> >> + else if ((temp < trip_temp) &&
> >> + (--inst_id <= max_state))
> >> + cdev->ops->set_cur_state(cdev, inst_id);
> >> +
> >> + 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 796f1ff..8df901f 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@xxxxxxxxxxxxxxxxxxxxxxxxxx
> https://lists.linuxfoundation.org/mailman/listinfo/linux-pm
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Next message: Daniel Lezcano: "Re: [PATCH] cpuidle: Avoid possible NULL pointer dereference in __cpuidle_register_device()"
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Next in thread: Amit Kachhap: "Re: [linux-pm] [PATCH 1/4] thermal: Add a new trip type to usecooling device instance number"
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