linux-kernel - Re: [PATCH v4 2/4] media: imx-jpeg: Use devm_pm_runtime

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Message-ID: <aYNo_XjfrXA6tKX-@lizhi-Precision-Tower-5810>
Date: Wed, 4 Feb 2026 10:42:53 -0500
From: Frank Li <Frank.li@....com>
To: "Ming Qian(OSS)" <ming.qian@....nxp.com>
Cc: mchehab@...nel.org, hverkuil-cisco@...all.nl,
	mirela.rabulea@....nxp.com, nicolas@...fresne.ca,
	shawnguo@...nel.org, s.hauer@...gutronix.de, kernel@...gutronix.de,
	festevam@...il.com, xiahong.bao@....com, eagle.zhou@....com,
	linux-imx@....com, imx@...ts.linux.dev, linux-media@...r.kernel.org,
	linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH v4 2/4] media: imx-jpeg: Use devm_pm_runtime_enable()
 helper

On Wed, Feb 04, 2026 at 09:36:06AM +0800, Ming Qian(OSS) wrote:
> Hi Frank,
>
> On 2/4/2026 12:56 AM, Frank Li wrote:
> > On Tue, Feb 03, 2026 at 04:23:39PM +0800, ming.qian@....nxp.com wrote:
> > > From: Ming Qian <ming.qian@....nxp.com>
> > >
> > > Use devm_pm_runtime_enable() to simplify probe and exit paths.
> > >
> > > No functional change.
> > >
> > > Signed-off-by: Ming Qian <ming.qian@....nxp.com>
> > > ---
> > >   drivers/media/platform/nxp/imx-jpeg/mxc-jpeg.c | 15 ++++++++++++---
> > >   1 file changed, 12 insertions(+), 3 deletions(-)
> > >
> > > diff --git a/drivers/media/platform/nxp/imx-jpeg/mxc-jpeg.c b/drivers/media/platform/nxp/imx-jpeg/mxc-jpeg.c
> > > index 39022c1bf36d..877e6c4f7406 100644
> > > --- a/drivers/media/platform/nxp/imx-jpeg/mxc-jpeg.c
> > > +++ b/drivers/media/platform/nxp/imx-jpeg/mxc-jpeg.c
> > > @@ -2971,12 +2971,22 @@ static int mxc_jpeg_probe(struct platform_device *pdev)
> > >   			  jpeg->dec_vdev->minor);
> > >
> > >   	platform_set_drvdata(pdev, jpeg);
> > > -	pm_runtime_enable(dev);
> > > +	ret = devm_pm_runtime_enable(dev);
> > > +	if (ret) {
> > > +		dev_err(dev, "Failed to enable runtime PM: %d\n", ret);
> > > +		goto err_pm;
> > > +	}
> > >
> > >   	return 0;
> > >
> > > +err_pm:
> > > +	video_unregister_device(jpeg->dec_vdev);
> > > +	/* set NULL to prevent double-free */
> > > +	jpeg->dec_vdev = NULL;
> >
> > code have not simplied, you add addtional goto label. You can use
> > devm_add_action_or_reset().
> >
> > Frank
> >
>
> I don't quite understand the difference compared to directly using
> devm_pm_runtime_enable.
>
> int devm_pm_runtime_enable(struct device *dev)
> {
> 	pm_runtime_enable(dev);
>
> 	return devm_add_action_or_reset(dev, pm_runtime_disable_action, dev);
> }
>
> We still need to check the return value of devm_add_action_or_reset and
> perform the corresponding error handling.
> We may still add the goto label.

Sorry, my means put video_device_release() to devm_add_action_or_reset() to
avoid goto.

If it is complex, you can keep original one.

Frank
>
> Regards,
> Ming
>
> > >   err_vdev_register:
> > > -	video_device_release(jpeg->dec_vdev);
> > > +	/* Only release if allocation succeeded but registration failed */
> > > +	if (jpeg->dec_vdev)
> > > +		video_device_release(jpeg->dec_vdev);
> > >
> > >   err_vdev_alloc:
> > >   	v4l2_m2m_release(jpeg->m2m_dev);
> > > @@ -3047,7 +3057,6 @@ static void mxc_jpeg_remove(struct platform_device *pdev)
> > >
> > >   	mxc_jpeg_free_slot_data(jpeg);
> > >
> > > -	pm_runtime_disable(&pdev->dev);
> > >   	video_unregister_device(jpeg->dec_vdev);
> > >   	v4l2_m2m_release(jpeg->m2m_dev);
> > >   	v4l2_device_unregister(&jpeg->v4l2_dev);
> > > --
> > > 2.52.0
> > >