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Date:   Wed, 17 Jun 2020 23:14:36 +0200
From:   Pavel Machek <pavel@ucw.cz>
To:     Thara Gopinath <thara.gopinath@linaro.org>
Cc:     rui.zhang@intel.com, ulf.hansson@linaro.org,
        daniel.lezcano@linaro.org, bjorn.andersson@linaro.org,
        agross@kernel.org, robh@kernel.org, amit.kucheria@verdurent.com,
        mark.rutland@arm.com, rjw@rjwysocki.net, linux-pm@vger.kernel.org,
        devicetree@vger.kernel.org, linux-arm-msm@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH v6 0/6] Introduce Power domain based warming device driver
Message-ID: <20200617211436.GA2078@bug>
References: <20200604015317.31389-1-thara.gopinath@linaro.org>
 <20200616105325.GH1718@bug>
 <0eb2e140-9c9c-4777-9916-d81eddc793ca@linaro.org>
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Hi!

> >>falls below certain threshold. These power domains can be considered as
> >>thermal warming devices.  (opposite of thermal cooling devices).
> >
> >Would you explain when this is needed?
> >
> >I'd normally expect "too low" temperature to be a problem during power-on, but at
> >that time Linux is not running so it can not provide the heating...
> Hi Pavel,
> 
> This is more in the scenario if the system in on and temperature is dipping
> (I have been told in colder climates). Idea is to turn on resources so as to
> prevent further dipping of temperature if possible.

I guess even that makes sense...

But, out of curiosity, do you know which kind of device is that and in what
kind of environment? I mean, theoretically it may make sense on a cellphone,
but... I guess you have some fun device and would like to know what it is :-).

Hmm. And we can make this quite generic.

while (too_cold())
	barrier();

Wasting power is really easy :-).
									Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html