linux-kernel - Re: [PATCH] devfreq: Suspend all devices on system shutdown

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Message-ID: <20190306231014.GE7915@amd>
Date:   Thu, 7 Mar 2019 00:10:14 +0100
From:   Pavel Machek <pavel@....cz>
To:     Marek Szyprowski <m.szyprowski@...sung.com>
Cc:     linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org,
        linux-samsung-soc@...r.kernel.org,
        MyungJoo Ham <myungjoo.ham@...sung.com>,
        Chanwoo Choi <cw00.choi@...sung.com>,
        Krzysztof Kozlowski <krzk@...nel.org>,
        Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>,
        Lukasz Luba <l.luba@...tner.samsung.com>,
        Markus Reichl <m.reichl@...etechno.de>
Subject: Re: [PATCH] devfreq: Suspend all devices on system shutdown

On Fri 2019-01-25 14:54:03, Marek Szyprowski wrote:
> This way devfreq core ensures that all its devices will be set to safe
> operation points before reboot operation. There are board on which some
> aggressive power saving operation points are behind the capabilities of
> the bootloader to properly reset the hardware and boot the board. This
> way one can avoid board crash early after reboot.
> 
> Similar pattern is used in CPUfreq subsystem.

This looks somehow dangerous to me. I guess this will break someone's
shutdown, and on battery-powered devices, that's quite bad thing to
do.

Could we explicitely do it only for devices that need it?
								Pavel
								
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

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