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References: <20220505015814.3727692-1-rui.zhang@intel.com> <40b8ad06-6ef2-113c-fffb-2fa001603b3f@suse.com>
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From:   "Rafael J. Wysocki" <rafael@kernel.org>
Date:   Thu, 5 May 2022 14:02:14 +0200
Message-ID: <CAJZ5v0hceDVkv05=SFbO53wsmHWkrs1SSoxZ=FuErYsnNutGWg@mail.gmail.com>
Subject: Re: [PATCH 0/7] PM: Solution for S0ix failure caused by PCH overheating
To:     Oliver Neukum <oneukum@suse.com>
Cc:     Zhang Rui <rui.zhang@intel.com>,
        "Rafael J. Wysocki" <rjw@rjwysocki.net>, kvalo@kernel.org,
        Alexandre Belloni <alexandre.belloni@bootlin.com>,
        Linux PM <linux-pm@vger.kernel.org>,
        ACPI Devel Maling List <linux-acpi@vger.kernel.org>,
        linux-rtc@vger.kernel.org,
        "open list:NETWORKING DRIVERS (WIRELESS)" 
        <linux-wireless@vger.kernel.org>,
        Daniel Lezcano <daniel.lezcano@linaro.org>,
        merez@codeaurora.org, mat.jonczyk@o2.pl,
        Sumeet Pawnikar <sumeet.r.pawnikar@intel.com>,
        Len Brown <len.brown@intel.com>
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On Thu, May 5, 2022 at 10:23 AM Oliver Neukum <oneukum@suse.com> wrote:
>
>
>
> On 05.05.22 03:58, Zhang Rui wrote:
> > On some Intel client platforms like SKL/KBL/CNL/CML, there is a
> > PCH thermal sensor that monitors the PCH temperature and blocks the system
> > from entering S0ix in case it overheats.
> >
> > Commit ef63b043ac86 ("thermal: intel: pch: fix S0ix failure due to PCH
> > temperature above threshold") introduces a delay loop to cool the
> > temperature down for this purpose.
> >
> > However, in practice, we found that the time it takes to cool the PCH down
> > below threshold highly depends on the initial PCH temperature when the
> > delay starts, as well as the ambient temperature.
>
> >
> > This patch series has been tested on the same Dell XPS 9360 laptop and
> > S0ix is 100% achieved across 1000+ s2idle iterations.
> >
> Hi,
>
> what is the user experience if this ever triggers? At that stage the
> system will appear to be suspended to an external observer, won't it?
> So in effect you'd have a system that spontaneously wakes up, won't you?

No, you won't.

It will just go ahead and reach S0ix when it can.  It will only wake
up if there's a legitimate wakeup even in the meantime.