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

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Message-ID: <e8ada353-3e65-4014-9b94-622be6180c5b@oss.nxp.com>
Date: Thu, 5 Feb 2026 09:45:41 +0800
From: "Ming Qian(OSS)" <ming.qian@....nxp.com>
To: Frank Li <Frank.li@....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

Hi Frank,

On 2/4/2026 11:42 PM, Frank Li wrote:
> 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

OK, I get your point, and I prefer to keep it.

Regards,
Ming

>>
>> 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
>>>>