Zhang Rui <rui.zhang@xxxxxxxxx> writes:
> After thermal zone device registered, as we have not read any
> temperature before, thus tz->temperature should not be 0, which actually
> means 0C, and thermal trend is not available.
> In this case, we need specially handling for the first
> thermal_zone_device_update().
>
> Both thermal core framework and step_wise governor is enhanced to handle this.
>
> CC: <stable@xxxxxxxxxxxxxxx> #3.18+
> Tested-by: Manuel Krause <manuelkrause@xxxxxxxxxxxx>
> Tested-by: szegad <szegadlo@xxxxxxxxxxxxxx>
> Tested-by: prash <prash.n.rao@xxxxxxxxx>
> Tested-by: amish <ammdispose-arch@xxxxxxxxx>
> Tested-by: Matthias <morpheusxyz123@xxxxxxxx>
> Signed-off-by: Zhang Rui <rui.zhang@xxxxxxxxx>
> ---
> drivers/thermal/step_wise.c | 15 +++++++++++++--
> drivers/thermal/thermal_core.c | 19 +++++++++++++++++--
> drivers/thermal/thermal_core.h | 1 +
> include/linux/thermal.h | 3 +++
> 4 files changed, 34 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/thermal/step_wise.c b/drivers/thermal/step_wise.c
> index 5a0f12d..c2bb37c 100644
> --- a/drivers/thermal/step_wise.c
> +++ b/drivers/thermal/step_wise.c
> @@ -63,6 +63,16 @@ static unsigned long get_target_state(struct thermal_instance *instance,
> next_target = instance->target;
> dev_dbg(&cdev->device, "cur_state=%ld\n", cur_state);
>
> + if (!instance->initialized) {
> + if (throttle) {
> + next_target = (cur_state + 1) >= instance->upper ?
> + instance->upper :
> + ((cur_state + 1) < instance->lower ?
> + instance->lower : (cur_state + 1));
> + } else
> + next_target = THERMAL_NO_TARGET;
> + }
> +
Instead of checking whether the instance has been initialised, you could
add THERMAL_TREND_INVALID to the thermal_trend enum. That can then be
handled in the switch case below instead of needing special case
handling like above.
What do you think?
> switch (trend) {
> case THERMAL_TREND_RAISING:
> if (throttle) {
> @@ -149,7 +159,8 @@ static void thermal_zone_trip_update(struct thermal_zone_device *tz, int trip)
> dev_dbg(&instance->cdev->device, "old_target=%d, target=%d\n",
> old_target, (int)instance->target);
>
> - if (old_target == instance->target)
> + if (instance->initialized &&
> + old_target == instance->target)
> continue;
>
> /* Activate a passive thermal instance */
> @@ -161,7 +172,7 @@ static void thermal_zone_trip_update(struct thermal_zone_device *tz, int trip)
> instance->target == THERMAL_NO_TARGET)
> update_passive_instance(tz, trip_type, -1);
>
> -
> + instance->initialized = true;
> instance->cdev->updated = false; /* cdev needs update */
> }
>
[...]
> diff --git a/drivers/thermal/thermal_core.h b/drivers/thermal/thermal_core.h
> index 0531c75..6d9ffa5 100644
> --- a/drivers/thermal/thermal_core.h
> +++ b/drivers/thermal/thermal_core.h
> @@ -41,6 +41,7 @@ struct thermal_instance {
> struct thermal_zone_device *tz;
> struct thermal_cooling_device *cdev;
> int trip;
> + bool initialized;
> unsigned long upper; /* Highest cooling state for this trip point */
> unsigned long lower; /* Lowest cooling state for this trip point */
> unsigned long target; /* expected cooling state */
> diff --git a/include/linux/thermal.h b/include/linux/thermal.h
> index 5eac316..8650b0b 100644
> --- a/include/linux/thermal.h
> +++ b/include/linux/thermal.h
> @@ -40,6 +40,9 @@
> /* No upper/lower limit requirement */
> #define THERMAL_NO_LIMIT ((u32)~0)
>
> +/* Invalid/uninitialized temperature */
> +#define THERMAL_TEMP_INVALID -27400
> +
Did you mean -274000 (note the missing '0') which is < 0K? A comment
would be helpful for anybody reading the code. Took me a while to parse
it.
> /* Unit conversion macros */
> #define KELVIN_TO_CELSIUS(t) (long)(((long)t-2732 >= 0) ? \
> ((long)t-2732+5)/10 : ((long)t-2732-5)/10)
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