Add X403, a 3 plane 10 bits per component non-subsampled YCbCr format.

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Reviewed-by: Vishal Sagar <vishal.sagar@amd.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
---
 drivers/gpu/drm/drm_fourcc.c  | 3 +++
 include/uapi/drm/drm_fourcc.h | 9 +++++++++
 2 files changed, 12 insertions(+)

diff --git a/drivers/gpu/drm/drm_fourcc.c b/drivers/gpu/drm/drm_fourcc.c
index 4fc1880603bc..de8c98b166f1 100644
--- a/drivers/gpu/drm/drm_fourcc.c
+++ b/drivers/gpu/drm/drm_fourcc.c
@@ -388,6 +388,9 @@ const struct drm_format_info *__drm_format_info(u32 format)
 		{ .format = DRM_FORMAT_XYYY2101010,	.depth = 0,  .num_planes = 1,
 		  .char_per_block = { 4, 0, 0 }, .block_w = { 3, 0, 0 }, .block_h = { 1, 0, 0 },
 		  .hsub = 1, .vsub = 1, .is_yuv = true },
+		{ .format = DRM_FORMAT_X403,		.depth = 0,  .num_planes = 3,
+		  .char_per_block = { 4, 4, 4 }, .block_w = { 3, 3, 3 }, .block_h = { 1, 1, 1 },
+		  .hsub = 1, .vsub = 1, .is_yuv = true },
 	};
 
 	unsigned int i;
diff --git a/include/uapi/drm/drm_fourcc.h b/include/uapi/drm/drm_fourcc.h
index c6d4754ec202..385da5942716 100644
--- a/include/uapi/drm/drm_fourcc.h
+++ b/include/uapi/drm/drm_fourcc.h
@@ -402,6 +402,15 @@ extern "C" {
  */
 #define DRM_FORMAT_Q401		fourcc_code('Q', '4', '0', '1')
 
+/*
+ * 3 plane non-subsampled (444) YCbCr
+ * 10 bpc, 30 bits per sample image data in a single contiguous buffer.
+ * index 0: Y plane,  [31:0] x:Y2:Y1:Y0    [2:10:10:10] little endian
+ * index 1: Cb plane, [31:0] x:Cb2:Cb1:Cb0 [2:10:10:10] little endian
+ * index 2: Cr plane, [31:0] x:Cr2:Cr1:Cr0 [2:10:10:10] little endian
+ */
+#define DRM_FORMAT_X403		fourcc_code('X', '4', '0', '3')
+
 /*
  * 3 plane YCbCr LSB aligned
  * In order to use these formats in a similar fashion to MSB aligned ones

-- 
2.43.0

On Wednesday, March 25th, 2026 at 15:02, Tomi Valkeinen <tomi.valkeinen@ideasonboard.com> wrote:

> +/*
> + * 3 plane non-subsampled (444) YCbCr
> + * 10 bpc, 30 bits per sample image data in a single contiguous buffer.
> + * index 0: Y plane,  [31:0] x:Y2:Y1:Y0    [2:10:10:10] little endian
> + * index 1: Cb plane, [31:0] x:Cb2:Cb1:Cb0 [2:10:10:10] little endian
> + * index 2: Cr plane, [31:0] x:Cr2:Cr1:Cr0 [2:10:10:10] little endian
> + */
> +#define DRM_FORMAT_X403		fourcc_code('X', '4', '0', '3')

So, this one is different from the Q family, because Q has padding in
LSB rather than MSB. Speaking of, maybe we should add "LSB aligned" to
the doc comment to make that clear?

Re-reading the sibling thread about DRM_FORMAT_XV20, sounds like the
first digit matches my expectations for sub-sampling. How did you pick
the last two digits? I think I would've expected "30" here rather than
"03", since the last two planes are Cb Cr rather than Cr Cb.

Has the first "X" letter been picked arbitrarily? It's already used to
denote padding in other formats so I wonder if we should pick that
instead of, say, "T".

Simon