> -----Original Message----- > From: Punit Agrawal [mailto:punit.agrawal@xxxxxxx] > Sent: Thursday, March 26, 2015 8:41 PM > To: Zhang, Rui > Cc: linux-pm@xxxxxxxxxxxxxxx; stable@xxxxxxxxxxxxxxx > Subject: Re: [PATCH V2 1/3] Thermal: initialize thermal zone device correctly > Importance: High > > 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? > Well, that's what I did in my initial proposal, but I found it is not enough. Say, for the problem fixed in patch 3/3, when a cooling device is registered after the thermal zone, the thermal trend is not THEMAL_TREND_INVALID, but we need to get a proper cooling state for the newly registered cooling device. Thus a per thermal_instance flag is introduced instead. Thanks, rui > > 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) -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html