linux-kernel - Re: [PATCH] Input: omap-keypad - fix runtime pm imbalance on error

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Message-ID: <CAKdAkRTyVL0uV0dGxHoEgMyB9FP6b0m60CHy7C4QXeR5WTGAJw@mail.gmail.com>
Date:   Wed, 20 May 2020 10:02:27 -0700
From:   Dmitry Torokhov <dmitry.torokhov@...il.com>
To:     Dinghao Liu <dinghao.liu@....edu.cn>,
        "Rafael J. Wysocki" <rafael@...nel.org>
Cc:     Kangjie Lu <kjlu@....edu>, Richard Fontana <rfontana@...hat.com>,
        Allison Randal <allison@...utok.net>,
        Thomas Gleixner <tglx@...utronix.de>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        "linux-input@...r.kernel.org" <linux-input@...r.kernel.org>,
        lkml <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] Input: omap-keypad - fix runtime pm imbalance on error

Hi Dinghao,

On Wed, May 20, 2020 at 6:35 AM Dinghao Liu <dinghao.liu@....edu.cn> wrote:
>
> pm_runtime_get_sync() increments the runtime PM usage counter even
> the call returns an error code. Thus a pairing decrement is needed
> on the error handling path to keep the counter balanced.

This is a very surprising behavior and I wonder if this should be
fixed in the PM core (or the required cleanup steps need to be called
out in the function description). I also see that a few drivers that
handle this situation correctly (?) call pm_runtime_put_noidle()
instead of pm_runtime_put_sync() in the error path.

Rafael, do you have any guidance here?

Thanks.

-- 
Dmitry