linux-kernel - Re: [PATCH v9 03/17] ARM: tegra: Remove pen-locking from cpuidle-tegra20

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Message-ID: <20200221145847.GH10516@linaro.org>
Date:   Fri, 21 Feb 2020 15:58:47 +0100
From:   Daniel Lezcano <daniel.lezcano@...aro.org>
To:     Dmitry Osipenko <digetx@...il.com>
Cc:     Thierry Reding <thierry.reding@...il.com>,
        Jonathan Hunter <jonathanh@...dia.com>,
        Peter De Schrijver <pdeschrijver@...dia.com>,
        "Rafael J. Wysocki" <rjw@...ysocki.net>,
        Michał Mirosław <mirq-linux@...e.qmqm.pl>,
        Jasper Korten <jja2000@...il.com>,
        David Heidelberg <david@...t.cz>,
        Peter Geis <pgwipeout@...il.com>, linux-pm@...r.kernel.org,
        linux-tegra@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v9 03/17] ARM: tegra: Remove pen-locking from
 cpuidle-tegra20

On Thu, Feb 13, 2020 at 02:51:20AM +0300, Dmitry Osipenko wrote:
> Pen-locking is meant to block CPU0 if CPU1 wakes up during of entering
> into LP2 because of some interrupt firing up, preventing unnecessary LP2
> enter that will be resumed immediately. Apparently this case doesn't
> happen often in practice, I checked how often it takes place and found
> that after ~20 hours of browsing web, managing email, watching videos and
> idling (15+ hours) there is only a dozen of early LP2 entering abortions
> and they all happened while device was idling. Thus let's remove the
> pen-locking and make LP2 entering uninterruptible, simplifying code quite
> a lot. This will also become very handy for the upcoming unified cpuidle
> driver, allowing to have a common LP2 code-path across of different
> hardware generations.
> 
> Acked-by: Peter De Schrijver <pdeschrijver@...dia.com>
> Tested-by: Peter Geis <pgwipeout@...il.com>
> Tested-by: Jasper Korten <jja2000@...il.com>
> Tested-by: David Heidelberg <david@...t.cz>
> Signed-off-by: Dmitry Osipenko <digetx@...il.com>

Acked-by: Daniel Lezcano <daniel.lezcano@...aro.org>