[PATCH v1] thermal: core: Call monitor_thermal_zone() if zone temperature is invalid

["Rafael J. Wysocki" <rjw@rjwysocki.net>]

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

Commit 202aa0d4bb53 ("thermal: core: Do not call handle_thermal_trip()
if zone temperature is invalid") caused __thermal_zone_device_update()
to return early if the current thermal zone temperature was invalid.

This was done to avoid running handle_thermal_trip() and governor
callbacks in that case which led to confusion.  However, it went too
far because monitor_thermal_zone() still needs to be called even when
the zone temperature is invalid to ensure that it will be updated
eventually in case thermal polling is enabled and the driver has no
other means to notify the core of zone temperature changes (for example,
it does not register an interrupt handler or ACPI notifier).

Accordingly, make __thermal_zone_device_update() call
monitor_thermal_zone() when it skips the other actions due to
invalid zone temperature.

Fixes: 202aa0d4bb53 ("thermal: core: Do not call handle_thermal_trip() if zone temperature is invalid")
Reported-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
 drivers/thermal/thermal_core.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

Index: linux-pm/drivers/thermal/thermal_core.c
===================================================================
--- linux-pm.orig/drivers/thermal/thermal_core.c
+++ linux-pm/drivers/thermal/thermal_core.c
@@ -514,7 +514,7 @@ void __thermal_zone_device_update(struct
 	update_temperature(tz);
 
 	if (tz->temperature == THERMAL_TEMP_INVALID)
-		return;
+		goto monitor;
 
 	tz->notify_event = event;
 
@@ -536,6 +536,7 @@ void __thermal_zone_device_update(struct
 
 	thermal_debug_update_trip_stats(tz);
 
+monitor:
 	monitor_thermal_zone(tz);
 }