mirror of https://lore.kernel.org/lkml/
 help / color / mirror / Atom feed
From: "Rafael J. Wysocki" <rjw@rjwysocki.net>
To: Linux PM <linux-pm@vger.kernel.org>,
	Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: LKML <linux-kernel@vger.kernel.org>, Lukasz Luba <lukasz.luba@arm.com>
Subject: [PATCH v1] thermal: trip: Avoid skipping trips in thermal_zone_set_trips()
Date: Tue, 30 Jul 2024 16:41:18 +0200	[thread overview]
Message-ID: <12509184.O9o76ZdvQC@rjwysocki.net> (raw)

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

Say there are 3 trip points A, B, C sorted in ascending temperature
order with no hysteresis.  If the zone temerature is exactly equal to
B, thermal_zone_set_trips() will set the boundaries to A and C and the
hardware will not catch any crossing of B (either way) until either A
or C is crossed and the boundaries are changed.

To avoid that, use non-strict inequalities when comparing the trip
threshold to the zone temperature in thermal_zone_set_trips().

In the example above, it will cause both boundaries to be set to B,
which is desirable because an interrupt will trigger when the zone
temperature becomes different from B regardless of which way it goes.
That will allow a new interval to be set depending on the direction of
the zone temperature change.

Fixes: 893bae92237d ("thermal: trip: Make thermal_zone_set_trips() use trip thresholds")
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---

6.11-rc material.

---
 drivers/thermal/thermal_trip.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

Index: linux-pm/drivers/thermal/thermal_trip.c
===================================================================
--- linux-pm.orig/drivers/thermal/thermal_trip.c
+++ linux-pm/drivers/thermal/thermal_trip.c
@@ -82,10 +82,10 @@ void thermal_zone_set_trips(struct therm
 		return;
 
 	for_each_trip_desc(tz, td) {
-		if (td->threshold < tz->temperature && td->threshold > low)
+		if (td->threshold <= tz->temperature && td->threshold > low)
 			low = td->threshold;
 
-		if (td->threshold > tz->temperature && td->threshold < high)
+		if (td->threshold >= tz->temperature && td->threshold < high)
 			high = td->threshold;
 	}
 




             reply	other threads:[~2024-07-30 14:41 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-07-30 14:41 Rafael J. Wysocki [this message]
2024-07-30 14:57 ` Daniel Lezcano
2024-07-30 16:46   ` Rafael J. Wysocki
2024-07-30 20:17     ` Rafael J. Wysocki
2024-07-31 10:08     ` Daniel Lezcano

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=12509184.O9o76ZdvQC@rjwysocki.net \
    --to=rjw@rjwysocki.net \
    --cc=daniel.lezcano@linaro.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-pm@vger.kernel.org \
    --cc=lukasz.luba@arm.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox

all inboxes | Powered by JetHome®