Re: [PATCH v2] drm: drm_fourcc: add NV15, Q410, Q401 YUV formats

[Daniel Vetter <daniel@ffwll.ch>]

On Fri, May 29, 2020 at 12:47:26PM +0100, Ben Davis wrote:
> DRM_FORMAT_NV15 is a 2 plane format suitable for linear and 16x16

Is there a specific modifier for this 16x16 block linear format? Feels a
bit confusing, would be great to add that to the commit message so usage
is clearer. We have DRM_FORMAT_MOD_SAMSUNG_16_16_TILE, maybe that needs
another name (but same number) if this is commonly used across multiple
different gpu.
-Daniel



> block-linear memory layouts. The format is similar to P010 with 4:2:0
> sub-sampling but has no padding between components. Instead, luminance
> and chrominance samples are grouped into 4s so that each group is packed
> into an integer number of bytes:
> 
> YYYY = UVUV = 4 * 10 bits = 40 bits = 5 bytes
> 
> The '15' suffix refers to the optimum effective bits per pixel which is
> achieved when the total number of luminance samples is a multiple of 8.
> 
> Q410 and Q401 are both 3 plane non-subsampled formats with 16 bits per
> component, but only 10 bits are used and 6 are padded. 'Q' is chosen
> as the first letter to denote 3 plane YUV444, (and is the next letter
> along from P which is usually 2 plane).
> 
> V2: Updated block_w of NV15 to {4, 2, 0}
> 
> NV15:
> Tested-by: Jonas Karlman <jonas@kwiboo.se>
> 
> Reviewed-by: Brian Starkey <brian.starkey@arm.com>
> Signed-off-by: Ben Davis <ben.davis@arm.com>
> ---
>  drivers/gpu/drm/drm_fourcc.c  | 12 ++++++++++++
>  include/uapi/drm/drm_fourcc.h | 24 ++++++++++++++++++++++++
>  2 files changed, 36 insertions(+)
> 
> diff --git a/drivers/gpu/drm/drm_fourcc.c b/drivers/gpu/drm/drm_fourcc.c
> index b234bfaeda06..722c7ebe4e88 100644
> --- a/drivers/gpu/drm/drm_fourcc.c
> +++ b/drivers/gpu/drm/drm_fourcc.c
> @@ -274,6 +274,18 @@ const struct drm_format_info *__drm_format_info(u32 format)
>  		{ .format = DRM_FORMAT_YUV420_10BIT,    .depth = 0,
>  		  .num_planes = 1, .cpp = { 0, 0, 0 }, .hsub = 2, .vsub = 2,
>  		  .is_yuv = true },
> +		{ .format = DRM_FORMAT_NV15,		.depth = 0,
> +		  .num_planes = 2, .char_per_block = { 5, 5, 0 },
> +		  .block_w = { 4, 2, 0 }, .block_h = { 1, 1, 0 }, .hsub = 2,
> +		  .vsub = 2, .is_yuv = true },
> +		{ .format = DRM_FORMAT_Q410,		.depth = 0,
> +		  .num_planes = 3, .char_per_block = { 2, 2, 2 },
> +		  .block_w = { 1, 1, 1 }, .block_h = { 1, 1, 1 }, .hsub = 0,
> +		  .vsub = 0, .is_yuv = true },
> +		{ .format = DRM_FORMAT_Q401,		.depth = 0,
> +		  .num_planes = 3, .char_per_block = { 2, 2, 2 },
> +		  .block_w = { 1, 1, 1 }, .block_h = { 1, 1, 1 }, .hsub = 0,
> +		  .vsub = 0, .is_yuv = true },
>  	};
>  
>  	unsigned int i;
> diff --git a/include/uapi/drm/drm_fourcc.h b/include/uapi/drm/drm_fourcc.h
> index 9e488d10f8b4..bed51236aed9 100644
> --- a/include/uapi/drm/drm_fourcc.h
> +++ b/include/uapi/drm/drm_fourcc.h
> @@ -236,6 +236,12 @@ extern "C" {
>  #define DRM_FORMAT_NV61		fourcc_code('N', 'V', '6', '1') /* 2x1 subsampled Cb:Cr plane */
>  #define DRM_FORMAT_NV24		fourcc_code('N', 'V', '2', '4') /* non-subsampled Cr:Cb plane */
>  #define DRM_FORMAT_NV42		fourcc_code('N', 'V', '4', '2') /* non-subsampled Cb:Cr plane */
> +/*
> + * 2 plane YCbCr
> + * index 0 = Y plane, [39:0] Y3:Y2:Y1:Y0 little endian
> + * index 1 = Cr:Cb plane, [39:0] Cr1:Cb1:Cr0:Cb0 little endian
> + */
> +#define DRM_FORMAT_NV15		fourcc_code('N', 'V', '1', '5') /* 2x2 subsampled Cr:Cb plane */
>  
>  /*
>   * 2 plane YCbCr MSB aligned
> @@ -265,6 +271,24 @@ extern "C" {
>   */
>  #define DRM_FORMAT_P016		fourcc_code('P', '0', '1', '6') /* 2x2 subsampled Cr:Cb plane 16 bits per channel */
>  
> +
> +/* 3 plane non-subsampled (444) YCbCr
> + * 16 bits per component, but only 10 bits are used and 6 bits are padded
> + * index 0: Y plane, [15:0] Y:x [10:6] little endian
> + * index 1: Cb plane, [15:0] Cb:x [10:6] little endian
> + * index 2: Cr plane, [15:0] Cr:x [10:6] little endian
> + */
> +#define DRM_FORMAT_Q410		fourcc_code('Q', '4', '1', '0')
> +
> +/* 3 plane non-subsampled (444) YCrCb
> + * 16 bits per component, but only 10 bits are used and 6 bits are padded
> + * index 0: Y plane, [15:0] Y:x [10:6] little endian
> + * index 1: Cr plane, [15:0] Cr:x [10:6] little endian
> + * index 2: Cb plane, [15:0] Cb:x [10:6] little endian
> + */
> +#define DRM_FORMAT_Q401		fourcc_code('Q', '4', '0', '1')
> +
> +
>  /*
>   * 3 plane YCbCr
>   * index 0: Y plane, [7:0] Y
> -- 
> 2.24.0
> 

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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