linux-kernel - Re: [PATCH v2 4/4] media: uvcvideo: Set unique entity name based in type

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Message-ID: <a1c9639e-c6e1-b05a-e24c-f02ddad167ca@xs4all.nl>
Date:   Tue, 7 Dec 2021 10:57:05 +0100
From:   Hans Verkuil <hverkuil-cisco@...all.nl>
To:     Ricardo Ribalda <ribalda@...omium.org>,
        Nicolas Dufresne <nicolas@...fresne.ca>,
        Laurent Pinchart <laurent.pinchart@...asonboard.com>,
        Mauro Carvalho Chehab <mchehab@...nel.org>,
        Sergey Senozhatsky <sergey.senozhatsky@...il.com>,
        linux-media@...r.kernel.org, linux-kernel@...r.kernel.org,
        tfiga@...omium.org
Subject: Re: [PATCH v2 4/4] media: uvcvideo: Set unique entity name based in
 type

On 07/12/2021 01:38, Ricardo Ribalda wrote:
> All the entities must have a unique name. We can have a descriptive and
> unique name by appending the function to their terminal link.
> 
> This is even resilient to multi chain devices.
> 
> Fixes v4l2-compliance:
> Media Controller ioctls:
>      fail: v4l2-test-media.cpp(205): v2_entity_names_set.find(key) != v2_entity_names_set.end()
>    test MEDIA_IOC_G_TOPOLOGY: FAIL
>      fail: v4l2-test-media.cpp(394): num_data_links != num_links
>    test MEDIA_IOC_ENUM_ENTITIES/LINKS: FAIL
> 
> Signed-off-by: Ricardo Ribalda <ribalda@...omium.org>

Reviewed-by: Hans Verkuil <hverkuil-cisco@...all.nl>

Thanks!

	Hans

> ---
>  drivers/media/usb/uvc/uvc_driver.c | 13 +++++++++++++
>  1 file changed, 13 insertions(+)
> 
> diff --git a/drivers/media/usb/uvc/uvc_driver.c b/drivers/media/usb/uvc/uvc_driver.c
> index 058d28a0344b..8efbde981480 100644
> --- a/drivers/media/usb/uvc/uvc_driver.c
> +++ b/drivers/media/usb/uvc/uvc_driver.c
> @@ -2193,6 +2193,7 @@ int uvc_register_video_device(struct uvc_device *dev,
>  			      const struct v4l2_file_operations *fops,
>  			      const struct v4l2_ioctl_ops *ioctl_ops)
>  {
> +	const char __maybe_unused *name;
>  	int ret;
>  
>  	/* Initialize the video buffers queue. */
> @@ -2221,17 +2222,29 @@ int uvc_register_video_device(struct uvc_device *dev,
>  	case V4L2_BUF_TYPE_VIDEO_CAPTURE:
>  	default:
>  		vdev->device_caps = V4L2_CAP_VIDEO_CAPTURE | V4L2_CAP_STREAMING;
> +		name = "Video Capture";
>  		break;
>  	case V4L2_BUF_TYPE_VIDEO_OUTPUT:
>  		vdev->device_caps = V4L2_CAP_VIDEO_OUTPUT | V4L2_CAP_STREAMING;
> +		name = "Video Output";
>  		break;
>  	case V4L2_BUF_TYPE_META_CAPTURE:
>  		vdev->device_caps = V4L2_CAP_META_CAPTURE | V4L2_CAP_STREAMING;
> +		name = "Metadata";
>  		break;
>  	}
>  
> +	/*
> +	 * Many userspace applications identify the device with vdev->name, so
> +	 * we cannot change its name for its function.
> +	 */
>  	strscpy(vdev->name, dev->name, sizeof(vdev->name));
>  
> +#if defined(CONFIG_MEDIA_CONTROLLER)
> +	vdev->entity.name = devm_kasprintf(&stream->intf->dev, GFP_KERNEL,
> +				"%s %u", name, stream->header.bTerminalLink);
> +#endif
> +
>  	/*
>  	 * Set the driver data before calling video_register_device, otherwise
>  	 * the file open() handler might race us.
>