linux-kernel - Re: [PATCH] PM: runtime: Have devm_pm_runtime_enable() handle pm_runtime_dont_use

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Message-ID: <CAJZ5v0hOQS66hSWEFVSGsnpeoHCe_0UqHn3vQ_K9NhKv-HK3UQ@mail.gmail.com>
Date:   Fri, 4 Mar 2022 18:30:49 +0100
From:   "Rafael J. Wysocki" <rafael@...nel.org>
To:     Ulf Hansson <ulf.hansson@...aro.org>,
        Douglas Anderson <dianders@...omium.org>
Cc:     "Rafael J . Wysocki" <rafael@...nel.org>,
        Dmitry Baryshkov <dmitry.baryshkov@...aro.org>,
        Linus Walleij <linus.walleij@...aro.org>,
        Stephen Boyd <sboyd@...nel.org>,
        Laurent Pinchart <laurent.pinchart@...asonboard.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Len Brown <len.brown@...el.com>, Pavel Machek <pavel@....cz>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Linux PM <linux-pm@...r.kernel.org>
Subject: Re: [PATCH] PM: runtime: Have devm_pm_runtime_enable() handle pm_runtime_dont_use_autosuspend()

On Fri, Mar 4, 2022 at 11:04 AM Ulf Hansson <ulf.hansson@...aro.org> wrote:
>
> On Wed, 23 Feb 2022 at 17:35, Douglas Anderson <dianders@...omium.org> wrote:
> >
> > The PM Runtime docs say:
> >   Drivers in ->remove() callback should undo the runtime PM changes done
> >   in ->probe(). Usually this means calling pm_runtime_disable(),
> >   pm_runtime_dont_use_autosuspend() etc.
> >
> > From grepping code, it's clear that many people aren't aware of the
> > need to call pm_runtime_dont_use_autosuspend().
> >
> > When brainstorming solutions, one idea that came up was to leverage
> > the new-ish devm_pm_runtime_enable() function. The idea here is that:
> > * When the devm action is called we know that the driver is being
> >   removed. It's the perfect time to undo the use_autosuspend.
> > * The code of pm_runtime_dont_use_autosuspend() already handles the
> >   case of being called when autosuspend wasn't enabled.
> >
> > Suggested-by: Laurent Pinchart <laurent.pinchart@...asonboard.com>
> > Signed-off-by: Douglas Anderson <dianders@...omium.org>
>
> Okay, this provides an improvement from the short term perspective.

I agree.

> Reviewed-by: Ulf Hansson <ulf.hansson@...aro.org>

And so I've queued up the patch (for 5.18).

Thanks!