Re: [PATCH 5/5] usb: uvc: use v4l2_fill_fmtdesc instead of open coded format name

[Dan Scally <dan.scally@xxxxxxxxxxxxxxxx>]

Hi Michael

On 12/12/2022 19:47, Michael Grzeschik wrote:
> Since we have the helper function v4l2_fill_fmtdesc, we can use this to
> get the corresponding descriptive string for the pixelformat and set the
> compressed flag. This patch is removing the redundant name field in
> uvc_format_desc and makes use of v4l2_fill_fmtdesc instead.
>
> Signed-off-by: Michael Grzeschik <m.grzeschik@xxxxxxxxxxxxxx>
> ---


The only thing that makes me wary about this one is that it will change 
the format names reported by the uvcvideo driver to userspace, since 
those returned by v4l2_fill_fmtdesc() are not the same as the ones being 
dropped from uvc_format_desc[]...are we sure that's not going to matter?

>   drivers/media/common/uvc.c             | 37 --------------------------
>   drivers/media/usb/uvc/uvc_driver.c     |  8 +++++-
>   drivers/usb/gadget/function/uvc_v4l2.c |  6 +----
>   include/linux/usb/uvc.h                |  1 -
>   4 files changed, 8 insertions(+), 44 deletions(-)
>
> diff --git a/drivers/media/common/uvc.c b/drivers/media/common/uvc.c
> index a6787f1999becd..02de0dcad0f088 100644
> --- a/drivers/media/common/uvc.c
> +++ b/drivers/media/common/uvc.c
> @@ -11,187 +11,150 @@
>   
>   static const struct uvc_format_desc uvc_fmts[] = {
>   	{
> -		.name		= "YUV 4:2:2 (YUYV)",
>   		.guid		= UVC_GUID_FORMAT_YUY2,
>   		.fcc		= V4L2_PIX_FMT_YUYV,
>   	},
>   	{
> -		.name		= "YUV 4:2:2 (YUYV)",
>   		.guid		= UVC_GUID_FORMAT_YUY2_ISIGHT,
>   		.fcc		= V4L2_PIX_FMT_YUYV,
>   	},
>   	{
> -		.name		= "YUV 4:2:0 (NV12)",
>   		.guid		= UVC_GUID_FORMAT_NV12,
>   		.fcc		= V4L2_PIX_FMT_NV12,
>   	},
>   	{
> -		.name		= "MJPEG",
>   		.guid		= UVC_GUID_FORMAT_MJPEG,
>   		.fcc		= V4L2_PIX_FMT_MJPEG,
>   	},
>   	{
> -		.name		= "YVU 4:2:0 (YV12)",
>   		.guid		= UVC_GUID_FORMAT_YV12,
>   		.fcc		= V4L2_PIX_FMT_YVU420,
>   	},
>   	{
> -		.name		= "YUV 4:2:0 (I420)",
>   		.guid		= UVC_GUID_FORMAT_I420,
>   		.fcc		= V4L2_PIX_FMT_YUV420,
>   	},
>   	{
> -		.name		= "YUV 4:2:0 (M420)",
>   		.guid		= UVC_GUID_FORMAT_M420,
>   		.fcc		= V4L2_PIX_FMT_M420,
>   	},
>   	{
> -		.name		= "YUV 4:2:2 (UYVY)",
>   		.guid		= UVC_GUID_FORMAT_UYVY,
>   		.fcc		= V4L2_PIX_FMT_UYVY,
>   	},
>   	{
> -		.name		= "Greyscale 8-bit (Y800)",
>   		.guid		= UVC_GUID_FORMAT_Y800,
>   		.fcc		= V4L2_PIX_FMT_GREY,
>   	},
>   	{
> -		.name		= "Greyscale 8-bit (Y8  )",
>   		.guid		= UVC_GUID_FORMAT_Y8,
>   		.fcc		= V4L2_PIX_FMT_GREY,
>   	},
>   	{
> -		.name		= "Greyscale 8-bit (D3DFMT_L8)",
>   		.guid		= UVC_GUID_FORMAT_D3DFMT_L8,
>   		.fcc		= V4L2_PIX_FMT_GREY,
>   	},
>   	{
> -		.name		= "IR 8-bit (L8_IR)",
>   		.guid		= UVC_GUID_FORMAT_KSMEDIA_L8_IR,
>   		.fcc		= V4L2_PIX_FMT_GREY,
>   	},
>   	{
> -		.name		= "Greyscale 10-bit (Y10 )",
>   		.guid		= UVC_GUID_FORMAT_Y10,
>   		.fcc		= V4L2_PIX_FMT_Y10,
>   	},
>   	{
> -		.name		= "Greyscale 12-bit (Y12 )",
>   		.guid		= UVC_GUID_FORMAT_Y12,
>   		.fcc		= V4L2_PIX_FMT_Y12,
>   	},
>   	{
> -		.name		= "Greyscale 16-bit (Y16 )",
>   		.guid		= UVC_GUID_FORMAT_Y16,
>   		.fcc		= V4L2_PIX_FMT_Y16,
>   	},
>   	{
> -		.name		= "BGGR Bayer (BY8 )",
>   		.guid		= UVC_GUID_FORMAT_BY8,
>   		.fcc		= V4L2_PIX_FMT_SBGGR8,
>   	},
>   	{
> -		.name		= "BGGR Bayer (BA81)",
>   		.guid		= UVC_GUID_FORMAT_BA81,
>   		.fcc		= V4L2_PIX_FMT_SBGGR8,
>   	},
>   	{
> -		.name		= "GBRG Bayer (GBRG)",
>   		.guid		= UVC_GUID_FORMAT_GBRG,
>   		.fcc		= V4L2_PIX_FMT_SGBRG8,
>   	},
>   	{
> -		.name		= "GRBG Bayer (GRBG)",
>   		.guid		= UVC_GUID_FORMAT_GRBG,
>   		.fcc		= V4L2_PIX_FMT_SGRBG8,
>   	},
>   	{
> -		.name		= "RGGB Bayer (RGGB)",
>   		.guid		= UVC_GUID_FORMAT_RGGB,
>   		.fcc		= V4L2_PIX_FMT_SRGGB8,
>   	},
>   	{
> -		.name		= "RGB565",
>   		.guid		= UVC_GUID_FORMAT_RGBP,
>   		.fcc		= V4L2_PIX_FMT_RGB565,
>   	},
>   	{
> -		.name		= "BGR 8:8:8 (BGR3)",
>   		.guid		= UVC_GUID_FORMAT_BGR3,
>   		.fcc		= V4L2_PIX_FMT_BGR24,
>   	},
>   	{
> -		.name		= "H.264",
>   		.guid		= UVC_GUID_FORMAT_H264,
>   		.fcc		= V4L2_PIX_FMT_H264,
>   	},
>   	{
> -		.name		= "H.265",
>   		.guid		= UVC_GUID_FORMAT_H265,
>   		.fcc		= V4L2_PIX_FMT_HEVC,
>   	},
>   	{
> -		.name		= "Greyscale 8 L/R (Y8I)",
>   		.guid		= UVC_GUID_FORMAT_Y8I,
>   		.fcc		= V4L2_PIX_FMT_Y8I,
>   	},
>   	{
> -		.name		= "Greyscale 12 L/R (Y12I)",
>   		.guid		= UVC_GUID_FORMAT_Y12I,
>   		.fcc		= V4L2_PIX_FMT_Y12I,
>   	},
>   	{
> -		.name		= "Depth data 16-bit (Z16)",
>   		.guid		= UVC_GUID_FORMAT_Z16,
>   		.fcc		= V4L2_PIX_FMT_Z16,
>   	},
>   	{
> -		.name		= "Bayer 10-bit (SRGGB10P)",
>   		.guid		= UVC_GUID_FORMAT_RW10,
>   		.fcc		= V4L2_PIX_FMT_SRGGB10P,
>   	},
>   	{
> -		.name		= "Bayer 16-bit (SBGGR16)",
>   		.guid		= UVC_GUID_FORMAT_BG16,
>   		.fcc		= V4L2_PIX_FMT_SBGGR16,
>   	},
>   	{
> -		.name		= "Bayer 16-bit (SGBRG16)",
>   		.guid		= UVC_GUID_FORMAT_GB16,
>   		.fcc		= V4L2_PIX_FMT_SGBRG16,
>   	},
>   	{
> -		.name		= "Bayer 16-bit (SRGGB16)",
>   		.guid		= UVC_GUID_FORMAT_RG16,
>   		.fcc		= V4L2_PIX_FMT_SRGGB16,
>   	},
>   	{
> -		.name		= "Bayer 16-bit (SGRBG16)",
>   		.guid		= UVC_GUID_FORMAT_GR16,
>   		.fcc		= V4L2_PIX_FMT_SGRBG16,
>   	},
>   	{
> -		.name		= "Depth data 16-bit (Z16)",
>   		.guid		= UVC_GUID_FORMAT_INVZ,
>   		.fcc		= V4L2_PIX_FMT_Z16,
>   	},
>   	{
> -		.name		= "Greyscale 10-bit (Y10 )",
>   		.guid		= UVC_GUID_FORMAT_INVI,
>   		.fcc		= V4L2_PIX_FMT_Y10,
>   	},
>   	{
> -		.name		= "IR:Depth 26-bit (INZI)",
>   		.guid		= UVC_GUID_FORMAT_INZI,
>   		.fcc		= V4L2_PIX_FMT_INZI,
>   	},
>   	{
> -		.name		= "4-bit Depth Confidence (Packed)",
>   		.guid		= UVC_GUID_FORMAT_CNF4,
>   		.fcc		= V4L2_PIX_FMT_CNF4,
>   	},
>   	{
> -		.name		= "HEVC",
>   		.guid		= UVC_GUID_FORMAT_HEVC,
>   		.fcc		= V4L2_PIX_FMT_HEVC,
>   	},
> diff --git a/drivers/media/usb/uvc/uvc_driver.c b/drivers/media/usb/uvc/uvc_driver.c
> index 12b6ad0966d94a..af92e730bde7c7 100644
> --- a/drivers/media/usb/uvc/uvc_driver.c
> +++ b/drivers/media/usb/uvc/uvc_driver.c
> @@ -251,7 +251,13 @@ static int uvc_parse_format(struct uvc_device *dev,
>   		fmtdesc = uvc_format_by_guid(&buffer[5]);
>   
>   		if (fmtdesc != NULL) {
> -			strscpy(format->name, fmtdesc->name,
> +			struct v4l2_fmtdesc fmt;
> +
> +			fmt.pixelformat = fmtdesc->fcc;
> +
> +			v4l2_fill_fmtdesc(&fmt);
> +
> +			strscpy(format->name, fmt.description,
>   				sizeof(format->name));
>   			format->fcc = fmtdesc->fcc;
>   		} else {
> diff --git a/drivers/usb/gadget/function/uvc_v4l2.c b/drivers/usb/gadget/function/uvc_v4l2.c
> index 21e573e628f4e7..6e46fa1695f212 100644
> --- a/drivers/usb/gadget/function/uvc_v4l2.c
> +++ b/drivers/usb/gadget/function/uvc_v4l2.c
> @@ -374,14 +374,10 @@ uvc_v4l2_enum_format(struct file *file, void *fh, struct v4l2_fmtdesc *f)
>   	if (!uformat)
>   		return -EINVAL;
>   
> -	if (uformat->type != UVCG_UNCOMPRESSED)
> -		f->flags |= V4L2_FMT_FLAG_COMPRESSED;
> -
>   	fmtdesc = to_uvc_format(uformat);
>   	f->pixelformat = fmtdesc->fcc;
>   
> -	strscpy(f->description, fmtdesc->name, sizeof(f->description));
> -	f->description[strlen(fmtdesc->name) - 1] = 0;
> +	v4l2_fill_fmtdesc(f);
>   
>   	return 0;
>   }
> diff --git a/include/linux/usb/uvc.h b/include/linux/usb/uvc.h
> index 227a03f252a5c0..e407a7b8a91c70 100644
> --- a/include/linux/usb/uvc.h
> +++ b/include/linux/usb/uvc.h
> @@ -146,7 +146,6 @@
>   	 0x80, 0x00, 0x00, 0xaa, 0x00, 0x38, 0x9b, 0x71}
>   
>   struct uvc_format_desc {
> -	char *name;
>   	u8 guid[16];
>   	u32 fcc;
>   };