Re: [PATCH 5/9] media: qcom: camss: unconditionally set async notifier of subdevices

[neil.armstrong@linaro.org]

On 13/05/2025 16:23, Vladimir Zapolskiy wrote:
> For sake of simplicity it makes sense to register async notifier
> for all type of subdevices, both CAMSS components and sensors.
> 
> The case of sensors not connected to CAMSS is extraordinary and
> degenerate, it does not deserve any specific optimization.

Could you describe the difference on behavior in this case ? and how
it's still valid ?

Neil

> 
> Signed-off-by: Vladimir Zapolskiy <vladimir.zapolskiy@linaro.org>
> ---
>   drivers/media/platform/qcom/camss/camss.c | 30 ++++++-----------------
>   1 file changed, 8 insertions(+), 22 deletions(-)
> 
> diff --git a/drivers/media/platform/qcom/camss/camss.c b/drivers/media/platform/qcom/camss/camss.c
> index 976b70cc6d6a..4e91e4b6ef52 100644
> --- a/drivers/media/platform/qcom/camss/camss.c
> +++ b/drivers/media/platform/qcom/camss/camss.c
> @@ -3556,7 +3556,6 @@ static int camss_probe(struct platform_device *pdev)
>   {
>   	struct device *dev = &pdev->dev;
>   	struct camss *camss;
> -	int num_subdevs;
>   	int ret;
>   
>   	camss = devm_kzalloc(dev, sizeof(*camss), GFP_KERNEL);
> @@ -3627,11 +3626,9 @@ static int camss_probe(struct platform_device *pdev)
>   
>   	pm_runtime_enable(dev);
>   
> -	num_subdevs = camss_of_parse_ports(camss);
> -	if (num_subdevs < 0) {
> -		ret = num_subdevs;
> +	ret = camss_of_parse_ports(camss);
> +	if (ret < 0)
>   		goto err_v4l2_device_unregister;
> -	}
>   
>   	ret = camss_register_entities(camss);
>   	if (ret < 0)
> @@ -3647,23 +3644,12 @@ static int camss_probe(struct platform_device *pdev)
>   		goto err_register_subdevs;
>   	}
>   
> -	if (num_subdevs) {
> -		camss->notifier.ops = &camss_subdev_notifier_ops;
> -
> -		ret = v4l2_async_nf_register(&camss->notifier);
> -		if (ret) {
> -			dev_err(dev,
> -				"Failed to register async subdev nodes: %d\n",
> -				ret);
> -			goto err_media_device_unregister;
> -		}
> -	} else {
> -		ret = v4l2_device_register_subdev_nodes(&camss->v4l2_dev);
> -		if (ret < 0) {
> -			dev_err(dev, "Failed to register subdev nodes: %d\n",
> -				ret);
> -			goto err_media_device_unregister;
> -		}
> +	camss->notifier.ops = &camss_subdev_notifier_ops;
> +	ret = v4l2_async_nf_register(&camss->notifier);
> +	if (ret) {
> +		dev_err(dev,
> +			"Failed to register async subdev nodes: %d\n", ret);
> +		goto err_media_device_unregister;
>   	}
>   
>   	return 0;