[PATCH 1/4] drm: add RGB formats with separate alpha plane

[Daniel Vetter]

On Mon, Feb 27, 2017 at 12:52:46PM +0100, Philipp Zabel wrote:
> Some hardware can read the alpha components separately and then
> conditionally fetch color components only for non-zero alpha values.
> This patch adds fourcc definitions for two-plane RGB formats with an
> 8-bit alpha channel on a second plane.
> 
> Signed-off-by: Philipp Zabel <p.zabel at pengutronix.de>
> ---
>  drivers/gpu/drm/drm_fourcc.c  |  4 ++++
>  include/uapi/drm/drm_fourcc.h | 14 ++++++++++++++
>  2 files changed, 18 insertions(+)
> 
> diff --git a/drivers/gpu/drm/drm_fourcc.c b/drivers/gpu/drm/drm_fourcc.c
> index 90d2cc8da8eb6..e630a4dbf0b14 100644
> --- a/drivers/gpu/drm/drm_fourcc.c
> +++ b/drivers/gpu/drm/drm_fourcc.c
> @@ -144,6 +144,10 @@ const struct drm_format_info *__drm_format_info(u32 format)
>  		{ .format = DRM_FORMAT_ABGR8888,	.depth = 32, .num_planes = 1, .cpp = { 4, 0, 0 }, .hsub = 1, .vsub = 1 },
>  		{ .format = DRM_FORMAT_RGBA8888,	.depth = 32, .num_planes = 1, .cpp = { 4, 0, 0 }, .hsub = 1, .vsub = 1 },
>  		{ .format = DRM_FORMAT_BGRA8888,	.depth = 32, .num_planes = 1, .cpp = { 4, 0, 0 }, .hsub = 1, .vsub = 1 },
> +		{ .format = DRM_FORMAT_XRGB8888_A8,	.depth = 32, .num_planes = 2, .cpp = { 4, 1, 0 }, .hsub = 1, .vsub = 1 },
> +		{ .format = DRM_FORMAT_XBGR8888_A8,	.depth = 32, .num_planes = 2, .cpp = { 4, 1, 0 }, .hsub = 1, .vsub = 1 },
> +		{ .format = DRM_FORMAT_RGBX8888_A8,	.depth = 32, .num_planes = 2, .cpp = { 4, 1, 0 }, .hsub = 1, .vsub = 1 },
> +		{ .format = DRM_FORMAT_BGRX8888_A8,	.depth = 32, .num_planes = 2, .cpp = { 4, 1, 0 }, .hsub = 1, .vsub = 1 },
>  		{ .format = DRM_FORMAT_YUV410,		.depth = 0,  .num_planes = 3, .cpp = { 1, 1, 1 }, .hsub = 4, .vsub = 4 },
>  		{ .format = DRM_FORMAT_YVU410,		.depth = 0,  .num_planes = 3, .cpp = { 1, 1, 1 }, .hsub = 4, .vsub = 4 },
>  		{ .format = DRM_FORMAT_YUV411,		.depth = 0,  .num_planes = 3, .cpp = { 1, 1, 1 }, .hsub = 4, .vsub = 1 },
> diff --git a/include/uapi/drm/drm_fourcc.h b/include/uapi/drm/drm_fourcc.h
> index ef20abb8119bf..37cf9c871cebc 100644
> --- a/include/uapi/drm/drm_fourcc.h
> +++ b/include/uapi/drm/drm_fourcc.h
> @@ -114,6 +114,20 @@ extern "C" {
>  #define DRM_FORMAT_AYUV		fourcc_code('A', 'Y', 'U', 'V') /* [31:0] A:Y:Cb:Cr 8:8:8:8 little endian */
>  
>  /*
> + * 2 plane RGB + A
> + * index 0 = RGB plane

Maybe clarify the comment here with "RGB plane, same layout as the non _A8
RGB format has". Better to over-spec this stuff :-)
-Daniel

> + * index 1 = A plane
> + */
> +#define DRM_FORMAT_XRGB8888_A8	fourcc_code('X', 'R', 'A', '8')
> +#define DRM_FORMAT_XBGR8888_A8	fourcc_code('X', 'B', 'A', '8')
> +#define DRM_FORMAT_RGBX8888_A8	fourcc_code('R', 'X', 'A', '8')
> +#define DRM_FORMAT_BGRX8888_A8	fourcc_code('B', 'X', 'A', '8')
> +#define DRM_FORMAT_RGB888_A8	fourcc_code('R', '8', 'A', '8')
> +#define DRM_FORMAT_BGR888_A8	fourcc_code('B', '8', 'A', '8')
> +#define DRM_FORMAT_RGB565_A8	fourcc_code('R', '5', 'A', '8')
> +#define DRM_FORMAT_BGR565_A8	fourcc_code('B', '5', 'A', '8')
> +
> +/*
>   * 2 plane YCbCr
>   * index 0 = Y plane, [7:0] Y
>   * index 1 = Cr:Cb plane, [15:0] Cr:Cb little endian
> -- 
> 2.11.0
> 
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-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch