Re: [PATCH] media: usb: uvc: fill in description for unknown pixelformats

["Linux regression tracking (Thorsten Leemhuis)" <regressions@leemhuis.info>]

On 29.03.23 14:28, Hans Verkuil wrote:
> If the fcc is 0 (indicating an unknown GUID format), then fill in the
> description field in ENUM_FMT. Otherwise the V4L2 core will WARN.

What happened to this? It seems this fall through the cracks.

BTW:

> Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>

Afaics it might be good to have these in here:

Link: https://bugzilla.kernel.org/show_bug.cgi?id=217252
Link: https://bugzilla.redhat.com/show_bug.cgi?id=2180107

A comment in the former is what brought me here.

Ciao, Thorsten (wearing his 'the Linux kernel's regression tracker' hat)
--
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> Fixes: 50459f103edf ("media: uvcvideo: Remove format descriptions")
> ---
> diff --git a/drivers/media/usb/uvc/uvc_driver.c b/drivers/media/usb/uvc/uvc_driver.c
> index 7aefa76a42b3..2f1ced1212cd 100644
> --- a/drivers/media/usb/uvc/uvc_driver.c
> +++ b/drivers/media/usb/uvc/uvc_driver.c
> @@ -256,6 +256,9 @@ static int uvc_parse_format(struct uvc_device *dev,
>  		} else {
>  			dev_info(&streaming->intf->dev,
>  				 "Unknown video format %pUl\n", &buffer[5]);
> +			snprintf(format->name, sizeof(format->name), "%pUl\n",
> +				 &buffer[5]);
> +
>  			format->fcc = 0;
>  		}
> 
> diff --git a/drivers/media/usb/uvc/uvc_v4l2.c b/drivers/media/usb/uvc/uvc_v4l2.c
> index 35453f81c1d9..fc6f9e7d8506 100644
> --- a/drivers/media/usb/uvc/uvc_v4l2.c
> +++ b/drivers/media/usb/uvc/uvc_v4l2.c
> @@ -713,6 +713,10 @@ static int uvc_ioctl_enum_fmt(struct uvc_streaming *stream,
>  	if (format->flags & UVC_FMT_FLAG_COMPRESSED)
>  		fmt->flags |= V4L2_FMT_FLAG_COMPRESSED;
>  	fmt->pixelformat = format->fcc;
> +	if (format->name[0])
> +		strscpy(fmt->description, format->name,
> +			sizeof(fmt->description));
> +
>  	return 0;
>  }
> 
> diff --git a/drivers/media/usb/uvc/uvcvideo.h b/drivers/media/usb/uvc/uvcvideo.h
> index 9a596c8d894a..22656755a801 100644
> --- a/drivers/media/usb/uvc/uvcvideo.h
> +++ b/drivers/media/usb/uvc/uvcvideo.h
> @@ -264,6 +264,8 @@ struct uvc_format {
>  	u32 fcc;
>  	u32 flags;
> 
> +	char name[32];
> +
>  	unsigned int nframes;
>  	struct uvc_frame *frame;
>  };
>