diff mbox series

[1/6] thermal/core: Emit a warning if the thermal zone is updated without ops

Message ID 20210127030517.231260-2-kai.heng.feng@canonical.com
State New
Headers show
Series Prevent thermal shutdown during boot process | expand

Commit Message

Kai-Heng Feng Jan. 27, 2021, 3:05 a.m. UTC 
From: Daniel Lezcano <daniel.lezcano@linaro.org>

BugLink: https://bugs.launchpad.net/bugs/1906168

The actual code is silently ignoring a thermal zone update when a
driver is requesting it without a get_temp ops set.

That looks not correct, as the caller should not have called this
function if the thermal zone is unable to read the temperature.

That makes the code less robust as the check won't detect the driver
is inconsistently using the thermal API and that does not help to
improve the framework as these circumvolutions hide the problem at the
source.

In order to detect the situation when it happens, let's add a warning
when the update is requested without the get_temp() ops set.

Any warning emitted will have to be fixed at the source of the
problem: the caller must not call thermal_zone_device_update if there
is not get_temp callback set.

Cc: Thara Gopinath <thara.gopinath@linaro.org>
Cc: Amit Kucheria <amitk@kernel.org>
Cc: linux-pm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Reviewed-by: Lukasz Luba <lukasz.luba@arm.com>
Link: https://lore.kernel.org/r/20201210121514.25760-1-daniel.lezcano@linaro.org
(cherry picked from commit 433178e75834dc35f1ae79b56ec2cf396f2c6f3c)
Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
---
 drivers/thermal/thermal_core.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/drivers/thermal/thermal_core.c b/drivers/thermal/thermal_core.c
index b71196eaf90e..749001a88b44 100644
--- a/drivers/thermal/thermal_core.c
+++ b/drivers/thermal/thermal_core.c
@@ -467,7 +467,8 @@  void thermal_zone_device_update(struct thermal_zone_device *tz,
 	if (atomic_read(&in_suspend))
 		return;
 
-	if (!tz->ops->get_temp)
+	if (WARN_ONCE(!tz->ops->get_temp, "'%s' must not be called without "
+		      "'get_temp' ops set\n", __func__))
 		return;
 
 	update_temperature(tz);