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From:   "Rafael J. Wysocki" <rafael@kernel.org>
Date:   Mon, 25 Jan 2021 17:25:11 +0100
Message-ID: <CAJZ5v0ihGfW=8PRXZgLVMfwOCVJQQh=Kc+htqbYhBFvxgfYuZQ@mail.gmail.com>
Subject: Re: power-off delay/hang due to commit 6d25be57 (mainline)
To:     Stephen Berman <stephen.berman@gmx.net>
Cc:     "Rafael J. Wysocki" <rjw@rjwysocki.net>,
        Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
        Zhang Rui <rui.zhang@intel.com>,
        Robert Moore <robert.moore@intel.com>,
        Erik Kaneda <erik.kaneda@intel.com>,
        Len Brown <lenb@kernel.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Peter Zijlstra <peterz@infradead.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        ACPI Devel Maling List <linux-acpi@vger.kernel.org>,
        "open list:ACPI COMPONENT ARCHITECTURE (ACPICA)" <devel@acpica.org>,
        "Rafael J. Wysocki" <rafael@kernel.org>
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On Sun, Jan 24, 2021 at 2:49 PM Stephen Berman <stephen.berman@gmx.net> wrote:
>
> On Mon, 04 Jan 2021 16:38:43 +0100 Stephen Berman <stephen.berman@gmx.net> wrote:
>
> > On Thu, 31 Dec 2020 21:46:11 +0100 "Rafael J. Wysocki" <rjw@rjwysocki.net> wrote:
> >
> >> ATM, I'm tempted to do something like the patch below (with the rationale
> >> that it shouldn't be necessary to read the temperature right after updating
> >> the trip points if polling is in use, because the next update through polling
> >> will cause it to be read anyway and it will trigger trip point actions as
> >> needed).
> >>
> >> Stephen, can you give it a go, please?
> >
> > On Sat, 02 Jan 2021 12:03:17 +0100 "Rafael J. Wysocki" <rjw@rjwysocki.net> wrote:
> >
> >> There is one more way to address this, probably better: instead of checking the
> >> temperature right away in acpi_thermal_notify(), queue that on
> >> acpi_thermal_pm_queue
> >> and so only if another thermal check is not pending.
> >>
> >> This way there will be at most one temperature check coming from
> >> acpi_thermal_notify() queued up at any time which should prevent the
> >> build-up of work items from taking place.
> >>
> >> So something like this:
> >
> > Thanks for the patches.  I'll try them as soon as I can.
>
> FTR, since this is the thread I started for this bug, I've confirmed in
> https://lore.kernel.org/lkml/87y2gi78sg.fsf@gmx.net/T/#t that the latest
> patch fixes the bug.

OK, thanks!

The patch has been applied as 5.11-rc material.