linux-kernel - Re: [PATCH] ASoC: cs42l42: add missed regulator_bulk

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Date:   Tue, 10 Dec 2019 09:32:12 +0800
From:   Chuhong Yuan <hslester96@...il.com>
To:     Mark Brown <broonie@...nel.org>
Cc:     Brian Austin <brian.austin@...rus.com>,
        Paul Handrigan <Paul.Handrigan@...rus.com>,
        Liam Girdwood <lgirdwood@...il.com>,
        Jaroslav Kysela <perex@...ex.cz>,
        Takashi Iwai <tiwai@...e.com>,
        James Schulman <james.schulman@...rus.com>,
        alsa-devel@...a-project.org, LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] ASoC: cs42l42: add missed regulator_bulk_disable in
 remove and fix probe failure

On Tue, Dec 10, 2019 at 1:00 AM Mark Brown <broonie@...nel.org> wrote:
>
> On Tue, Dec 10, 2019 at 12:52:30AM +0800, Chuhong Yuan wrote:
>
> > I have a question that what if CONFIG_PM is not defined?
> > Since I have met runtime PM before in the patch
> > a31eda65ba21 ("net: fec: fix clock count mis-match").
> > I learned there that in some cases CONFIG_PM is not defined so runtime PM
> > cannot take effect.
> > Therefore, undo operations should still exist in remove functions.
>
> There's also the case where runtime PM is there and the device is active
> at suspend - it's not that there isn't a problem, it's that we can't
> unconditionally do a disable because we don't know if there was a
> matching enable.  It'll need to be conditional on the runtime PM state.

How about adding a check like #ifndef CONFIG_PM?
I use this in an old version of the mentioned patch.
However, that is not accepted since it seems not symmetric with enable
in the probe.
But I don't find an explicit runtime PM call in the probe here so the
revision pattern of
("net: fec: fix clock count mis-match") seems not applicable.
So I think adding a check is acceptable here, at least it solves the problem.