[PATCH v1] thermal: core: Drop trips_disabled bitmask

[PATCH v1] thermal: core: Drop trips_disabled bitmask

[Rafael J. Wysocki]

From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

After recent changes, thermal_zone_get_trip() cannot fail, as invoked
from thermal_zone_device_register_with_trips(), so the only role of
the trips_disabled bitmask is struct thermal_zone_device is to make
handle_thermal_trip() skip trip points whose temperature was initially
zero.  However, since the unit of temperature in the thermal core is
millicelsius, zero may very well be a valid temperature value at least
in some usage scenarios and the trip temperature may as well change
later.  Thus there is no reason to permanently disable trip points
with initial temperature equal to zero.

Accordingly, drop the trips_disabled bitmask along with the code
related to it.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
 drivers/thermal/thermal_core.c |   13 -------------
 include/linux/thermal.h        |    2 --
 2 files changed, 15 deletions(-)

Index: linux-pm/drivers/thermal/thermal_core.c
===================================================================
--- linux-pm.orig/drivers/thermal/thermal_core.c
+++ linux-pm/drivers/thermal/thermal_core.c
@@ -347,10 +347,6 @@ static void handle_thermal_trip(struct t
 {
 	struct thermal_trip trip;
 
-	/* Ignore disabled trip points */
-	if (test_bit(trip_id, &tz->trips_disabled))
-		return;
-
 	__thermal_zone_get_trip(tz, trip_id, &trip);
 
 	if (trip.temperature == THERMAL_TEMP_INVALID)
@@ -1231,7 +1227,6 @@ thermal_zone_device_register_with_trips(
 	struct thermal_zone_device *tz;
 	int id;
 	int result;
-	int count;
 	struct thermal_governor *governor;
 
 	if (!type || strlen(type) == 0) {
@@ -1328,14 +1323,6 @@ thermal_zone_device_register_with_trips(
 	if (result)
 		goto release_device;
 
-	for (count = 0; count < num_trips; count++) {
-		struct thermal_trip trip;
-
-		result = thermal_zone_get_trip(tz, count, &trip);
-		if (result || !trip.temperature)
-			set_bit(count, &tz->trips_disabled);
-	}
-
 	/* Update 'this' zone's governor information */
 	mutex_lock(&thermal_governor_lock);
 
Index: linux-pm/include/linux/thermal.h
===================================================================
--- linux-pm.orig/include/linux/thermal.h
+++ linux-pm/include/linux/thermal.h
@@ -122,7 +122,6 @@ struct thermal_cooling_device {
  * @devdata:	private pointer for device private data
  * @trips:	an array of struct thermal_trip
  * @num_trips:	number of trip points the thermal zone supports
- * @trips_disabled;	bitmap for disabled trips
  * @passive_delay_jiffies: number of jiffies to wait between polls when
  *			performing passive cooling.
  * @polling_delay_jiffies: number of jiffies to wait between polls when
@@ -163,7 +162,6 @@ struct thermal_zone_device {
 	void *devdata;
 	struct thermal_trip *trips;
 	int num_trips;
-	unsigned long trips_disabled;	/* bitmap for disabled trips */
 	unsigned long passive_delay_jiffies;
 	unsigned long polling_delay_jiffies;
 	int temperature;

Re: [PATCH v1] thermal: core: Drop trips_disabled bitmask

[Ido Schimmel]

On Tue, Sep 19, 2023 at 08:54:37PM +0200, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> 
> After recent changes, thermal_zone_get_trip() cannot fail, as invoked
> from thermal_zone_device_register_with_trips(), so the only role of
> the trips_disabled bitmask is struct thermal_zone_device is to make
> handle_thermal_trip() skip trip points whose temperature was initially
> zero.  However, since the unit of temperature in the thermal core is
> millicelsius, zero may very well be a valid temperature value at least
> in some usage scenarios and the trip temperature may as well change
> later.  Thus there is no reason to permanently disable trip points
> with initial temperature equal to zero.
> 
> Accordingly, drop the trips_disabled bitmask along with the code
> related to it.
> 
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

I guess I was copied because of commit f1b80a3878b2 ("thermal: core:
Restore behavior regarding invalid trip points"). Since then we stopped
relying on this behavior with commit 5601ef91fba8 ("mlxsw: core_thermal:
Use static trip points for transceiver modules").

Tested your patch and didn't see any regressions:

Tested-by: Ido Schimmel <idosch@nvidia.com>

Thanks

Re: [PATCH v1] thermal: core: Drop trips_disabled bitmask

[Rafael J. Wysocki]

On Wed, Sep 20, 2023 at 10:12 AM Ido Schimmel <idosch@nvidia.com> wrote:
>
> On Tue, Sep 19, 2023 at 08:54:37PM +0200, Rafael J. Wysocki wrote:
> > From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> >
> > After recent changes, thermal_zone_get_trip() cannot fail, as invoked
> > from thermal_zone_device_register_with_trips(), so the only role of
> > the trips_disabled bitmask is struct thermal_zone_device is to make
> > handle_thermal_trip() skip trip points whose temperature was initially
> > zero.  However, since the unit of temperature in the thermal core is
> > millicelsius, zero may very well be a valid temperature value at least
> > in some usage scenarios and the trip temperature may as well change
> > later.  Thus there is no reason to permanently disable trip points
> > with initial temperature equal to zero.
> >
> > Accordingly, drop the trips_disabled bitmask along with the code
> > related to it.
> >
> > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
>
> I guess I was copied because of commit f1b80a3878b2 ("thermal: core:
> Restore behavior regarding invalid trip points").

That's correct.

> Since then we stopped
> relying on this behavior with commit 5601ef91fba8 ("mlxsw: core_thermal:
> Use static trip points for transceiver modules").
>
> Tested your patch and didn't see any regressions:
>
> Tested-by: Ido Schimmel <idosch@nvidia.com>

Thank you!

Re: [PATCH v1] thermal: core: Drop trips_disabled bitmask

[Daniel Lezcano]

On 19/09/2023 20:54, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> 
> After recent changes, thermal_zone_get_trip() cannot fail, as invoked
> from thermal_zone_device_register_with_trips(), so the only role of
> the trips_disabled bitmask is struct thermal_zone_device is to make
> handle_thermal_trip() skip trip points whose temperature was initially
> zero.  However, since the unit of temperature in the thermal core is
> millicelsius, zero may very well be a valid temperature value at least
> in some usage scenarios and the trip temperature may as well change
> later.  Thus there is no reason to permanently disable trip points
> with initial temperature equal to zero.
> 
> Accordingly, drop the trips_disabled bitmask along with the code
> related to it.
> 
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

The logical change after changing how the trip point are handled ;)

Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>



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