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From: Andy Shevchenko <andy.shevchenko@gmail.com>
Date: Fri, 12 Apr 2024 16:43:43 +0300
Message-ID: <CAHp75VcKFCvzcESqsc8OQ5SVuO4gJiE5ZEUwkdoqvLzM=2PejQ@mail.gmail.com>
Subject: Re: [PATCH 2/2] media: i2c: Add GT97xx VCM driver
To: Sakari Ailus <sakari.ailus@linux.intel.com>
Cc: Zhi Mao <zhi.mao@mediatek.com>, Mauro Carvalho Chehab <mchehab@kernel.org>, 
	Rob Herring <robh@kernel.org>, Krzysztof Kozlowski <krzk+dt@kernel.org>, Conor Dooley <conor+dt@kernel.org>, 
	Matthias Brugger <matthias.bgg@gmail.com>, 
	AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>, 
	Philipp Zabel <p.zabel@pengutronix.de>, 
	Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>, 
	Heiko Stuebner <heiko@sntech.de>, Hans Verkuil <hverkuil-cisco@xs4all.nl>, 
	Hans de Goede <hdegoede@redhat.com>, Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>, 
	Alain Volmat <alain.volmat@foss.st.com>, Paul Elder <paul.elder@ideasonboard.com>, 
	Mehdi Djait <mehdi.djait@bootlin.com>, Bingbu Cao <bingbu.cao@intel.com>, 
	linux-media@vger.kernel.org, devicetree@vger.kernel.org, 
	linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, 
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On Fri, Apr 12, 2024 at 12:39=E2=80=AFPM Sakari Ailus
<sakari.ailus@linux.intel.com> wrote:
> On Wed, Apr 10, 2024 at 07:00:02PM +0300, Andy Shevchenko wrote:
> > > +static int gt97xx_open(struct v4l2_subdev *sd, struct v4l2_subdev_fh=
 *fh)
> > > +{
> > > +       return pm_runtime_resume_and_get(sd->dev);
> > > +}
> > > +
> > > +static int gt97xx_close(struct v4l2_subdev *sd, struct v4l2_subdev_f=
h *fh)
> > > +{
> > > +       return pm_runtime_put(sd->dev);
> > > +}
> >
> > Hmm... Shouldn't v4l2 take care about these (PM calls)?
>
> Ideally yes. We don't have a good mechanism for this at the moment as the
> lens isn't part of the image pipeline. Non-data links may be used for thi=
s
> in the future but that's not implemented yet.

Aren't you using devlinks? It was designed exactly to make sure that
the PM chain of calls goes in the correct order.

--=20
With Best Regards,
Andy Shevchenko