[PATCH v6 04/10] drm/vkms: Add atomic check and matrix handling for fixed matrix colorop

In vkms_plane_atomic_check(), validate that when a color pipeline
is active and the framebuffer format is YUV:
  - The first colorop must be DRM_COLOROP_FIXED_MATRIX
  - The fixed matrix colorop must not be bypassed

In vkms_plane_atomic_update(), when a color pipeline is active,
read the fixed_matrix_type from the first colorop state and map
it to the appropriate (color_encoding, color_range) pair for the
existing get_conversion_matrix_to_argb_u16() function.

In apply_colorop(), add a no-op case for DRM_COLOROP_FIXED_MATRIX
since the actual YUV-to-RGB conversion is already performed at
format read time via the conversion matrix.

Assisted-by: Claude:claude-opus-4.6
Signed-off-by: Harry Wentland <[email protected]>
Reviewed-by: Alex Hung <[email protected]>
Reviewed-by: Robert Mader <[email protected]>
---
 drivers/gpu/drm/vkms/tests/vkms_format_test.c |  2 +-
 drivers/gpu/drm/vkms/vkms_composer.c          |  6 ++
 drivers/gpu/drm/vkms/vkms_formats.c           |  9 +++
 drivers/gpu/drm/vkms/vkms_formats.h           |  2 +-
 drivers/gpu/drm/vkms/vkms_plane.c             | 55 ++++++++++++++++++-
 5 files changed, 71 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/vkms/tests/vkms_format_test.c b/drivers/gpu/drm/vkms/tests/vkms_format_test.c
index d2ae6321383b..bbb1ad18c99f 100644
--- a/drivers/gpu/drm/vkms/tests/vkms_format_test.c
+++ b/drivers/gpu/drm/vkms/tests/vkms_format_test.c
@@ -234,7 +234,7 @@ static void vkms_format_test_yuv_u16_to_argb_u16(struct kunit *test)
 		struct conversion_matrix matrix;
 
 		get_conversion_matrix_to_argb_u16
-			(DRM_FORMAT_NV12, param->encoding, param->range, &matrix);
+			(DRM_FORMAT_NV12, param->encoding, param->range, false, &matrix);
 
 		argb = argb_u16_from_yuv161616(&matrix, color->yuv.y, color->yuv.u,
 					       color->yuv.v);
diff --git a/drivers/gpu/drm/vkms/vkms_composer.c b/drivers/gpu/drm/vkms/vkms_composer.c
index 83d217085ad0..899120cd07ac 100644
--- a/drivers/gpu/drm/vkms/vkms_composer.c
+++ b/drivers/gpu/drm/vkms/vkms_composer.c
@@ -187,6 +187,12 @@ static void apply_colorop(struct pixel_argb_s32 *pixel, struct drm_colorop *colo
 		if (colorop_state->data)
 			apply_3x4_matrix(pixel,
 					 (struct drm_color_ctm_3x4 *)colorop_state->data->data);
+	} else if (colorop->type == DRM_COLOROP_FIXED_MATRIX) {
+		/*
+		 * Fixed Matrix is a no-op here. YUV-to-RGB conversion
+		 * is handled at format read time via the
+		 * conversion_matrix set in vkms_plane_atomic_update().
+		 */
 	}
 }
 
diff --git a/drivers/gpu/drm/vkms/vkms_formats.c b/drivers/gpu/drm/vkms/vkms_formats.c
index 4d5fcaeb82c5..964b574d9ed7 100644
--- a/drivers/gpu/drm/vkms/vkms_formats.c
+++ b/drivers/gpu/drm/vkms/vkms_formats.c
@@ -895,16 +895,25 @@ static void swap_uv_columns(struct conversion_matrix *matrix)
  * @format: DRM_FORMAT_* value for which to obtain a conversion function (see [drm_fourcc.h])
  * @encoding: DRM_COLOR_* value for which to obtain a conversion matrix
  * @range: DRM_COLOR_*_RANGE value for which to obtain a conversion matrix
+ * @bypass: If true, return an identity (no-op) matrix that passes the samples
+ *          through unchanged, ignoring @encoding and @range. Used when a fixed
+ *          matrix colorop is present but bypassed.
  * @matrix: Pointer to store the value into
  */
 void get_conversion_matrix_to_argb_u16(u32 format,
 				       enum drm_color_encoding encoding,
 				       enum drm_color_range range,
+				       bool bypass,
 				       struct conversion_matrix *matrix)
 {
 	const struct conversion_matrix *matrix_to_copy;
 	bool limited_range;
 
+	if (bypass) {
+		memcpy(matrix, &no_operation, sizeof(no_operation));
+		return;
+	}
+
 	switch (range) {
 	case DRM_COLOR_YCBCR_LIMITED_RANGE:
 		limited_range = true;
diff --git a/drivers/gpu/drm/vkms/vkms_formats.h b/drivers/gpu/drm/vkms/vkms_formats.h
index eeb208cdd6b1..d969cc669a5e 100644
--- a/drivers/gpu/drm/vkms/vkms_formats.h
+++ b/drivers/gpu/drm/vkms/vkms_formats.h
@@ -10,7 +10,7 @@ pixel_read_line_t get_pixel_read_line_function(u32 format);
 pixel_write_t get_pixel_write_function(u32 format);
 
 void get_conversion_matrix_to_argb_u16(u32 format, enum drm_color_encoding encoding,
-				       enum drm_color_range range,
+				       enum drm_color_range range, bool bypass,
 				       struct conversion_matrix *matrix);
 
 #if IS_ENABLED(CONFIG_KUNIT)
diff --git a/drivers/gpu/drm/vkms/vkms_plane.c b/drivers/gpu/drm/vkms/vkms_plane.c
index 68cb2a3335e6..6ee5c3f3207c 100644
--- a/drivers/gpu/drm/vkms/vkms_plane.c
+++ b/drivers/gpu/drm/vkms/vkms_plane.c
@@ -6,6 +6,7 @@
 #include <drm/drm_atomic.h>
 #include <drm/drm_atomic_helper.h>
 #include <drm/drm_blend.h>
+#include <drm/drm_colorop.h>
 #include <drm/drm_fourcc.h>
 #include <drm/drm_gem_atomic_helper.h>
 #include <drm/drm_gem_framebuffer_helper.h>
@@ -131,6 +132,9 @@ static void vkms_plane_atomic_update(struct drm_plane *plane,
 	struct drm_framebuffer *fb = new_state->fb;
 	struct vkms_frame_info *frame_info;
 	u32 fmt;
+	enum drm_color_encoding encoding = new_state->color_encoding;
+	enum drm_color_range range = new_state->color_range;
+	bool bypass = false;
 
 	if (!new_state->crtc || !fb)
 		return;
@@ -148,7 +152,49 @@ static void vkms_plane_atomic_update(struct drm_plane *plane,
 	frame_info->rotation = new_state->rotation;
 
 	vkms_plane_state->pixel_read_line = get_pixel_read_line_function(fmt);
-	get_conversion_matrix_to_argb_u16(fmt, new_state->color_encoding, new_state->color_range,
+
+	if (new_state->color_pipeline) {
+		struct drm_colorop *colorop = new_state->color_pipeline;
+		struct drm_colorop_state *colorop_state;
+
+		colorop_state = drm_atomic_get_new_colorop_state(state, colorop);
+		bypass = !colorop_state || colorop_state->bypass;
+
+		if (!bypass) {
+			switch (colorop_state->fixed_matrix_type) {
+			case DRM_COLOROP_FM_YCBCR601_FULL_RGB:
+				encoding = DRM_COLOR_YCBCR_BT601;
+				range = DRM_COLOR_YCBCR_FULL_RANGE;
+				break;
+			case DRM_COLOROP_FM_YCBCR601_LIMITED_RGB:
+				encoding = DRM_COLOR_YCBCR_BT601;
+				range = DRM_COLOR_YCBCR_LIMITED_RANGE;
+				break;
+			case DRM_COLOROP_FM_YCBCR709_FULL_RGB:
+				encoding = DRM_COLOR_YCBCR_BT709;
+				range = DRM_COLOR_YCBCR_FULL_RANGE;
+				break;
+			case DRM_COLOROP_FM_YCBCR709_LIMITED_RGB:
+				encoding = DRM_COLOR_YCBCR_BT709;
+				range = DRM_COLOR_YCBCR_LIMITED_RANGE;
+				break;
+			case DRM_COLOROP_FM_YCBCR2020_NC_FULL_RGB:
+				encoding = DRM_COLOR_YCBCR_BT2020;
+				range = DRM_COLOR_YCBCR_FULL_RANGE;
+				break;
+			case DRM_COLOROP_FM_YCBCR2020_NC_LIMITED_RGB:
+				encoding = DRM_COLOR_YCBCR_BT2020;
+				range = DRM_COLOR_YCBCR_LIMITED_RANGE;
+				break;
+			default:
+				encoding = DRM_COLOR_YCBCR_BT709;
+				range = DRM_COLOR_YCBCR_LIMITED_RANGE;
+				break;
+			}
+		}
+	}
+
+	get_conversion_matrix_to_argb_u16(fmt, encoding, range, bypass,
 					  &vkms_plane_state->conversion_matrix);
 }
 
@@ -175,6 +221,13 @@ static int vkms_plane_atomic_check(struct drm_plane *plane,
 	if (ret != 0)
 		return ret;
 
+	if (new_plane_state->color_pipeline && new_plane_state->fb->format->is_yuv) {
+		struct drm_colorop *colorop = new_plane_state->color_pipeline;
+
+		if (colorop->type != DRM_COLOROP_FIXED_MATRIX)
+			return -EINVAL;
+	}
+
 	return 0;
 }
 
-- 
2.55.0