[PATCH v2 01/13] drm/colorop: Add DRM_COLOROP_FIXED_MATRIX

Chaitanya Kumar Borah
2026-04-08T05:40:07Z

Introduce DRM_COLOROP_FIXED_MATRIX, a new colorop type representing a
hardware that performs a fixed matrix operation.

Unlike CTM-based colorops, this block does not expose programmable
coefficients. Instead, userspace selects one of the predefined
hardware modes via a new FIXED_MATRIX_TYPE enum property. Supported modes
include common YCbCr->RGB and RGB709->RGB2020 conversions.

v2:
- Naming changes (Pekka)

Signed-off-by: Chaitanya Kumar Borah <chaitanya.kumar.borah@intel.com>
---
drivers/gpu/drm/drm_atomic.c | 4 ++
drivers/gpu/drm/drm_atomic_uapi.c | 4 ++
drivers/gpu/drm/drm_colorop.c | 107 ++++++++++++++++++++++++++++++
include/drm/drm_colorop.h | 84 +++++++++++++++++++++++
include/uapi/drm/drm_mode.h | 12 ++++
5 files changed, 211 insertions(+)

diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c
index 41c57063f3b4..16a2183b11bf 100644
--- a/drivers/gpu/drm/drm_atomic.c
+++ b/drivers/gpu/drm/drm_atomic.c
@@ -845,6 +845,10 @@ static void drm_atomic_colorop_print_state(struct drm_printer *p,
drm_get_colorop_lut3d_interpolation_name(colorop->lut3d_interpolation));
drm_printf(p, "\tdata blob id=%d\n", state->data ? state->data->base.id : 0);
break;
+ case DRM_COLOROP_FIXED_MATRIX:
+ drm_printf(p, "\tfixed_matrix_type=%s\n",
+ drm_get_colorop_fixed_matrix_type_name(state->fixed_matrix_type));
+ break;
default:
break;
}
diff --git a/drivers/gpu/drm/drm_atomic_uapi.c b/drivers/gpu/drm/drm_atomic_uapi.c
index 5bd5bf6661df..d69406b08a0f 100644
--- a/drivers/gpu/drm/drm_atomic_uapi.c
+++ b/drivers/gpu/drm/drm_atomic_uapi.c
@@ -761,6 +761,8 @@ static int drm_atomic_colorop_set_property(struct drm_colorop *colorop,
} else if (property == colorop->data_property) {
return drm_atomic_color_set_data_property(colorop, state,
property, val);
+ } else if (property == colorop->fixed_matrix_type_property) {
+ state->fixed_matrix_type = val;
} else {
drm_dbg_atomic(colorop->dev,
"[COLOROP:%d:%d] unknown property [PROP:%d:%s]\n",
@@ -793,6 +795,8 @@ drm_atomic_colorop_get_property(struct drm_colorop *colorop,
*val = colorop->lut3d_interpolation;
else if (property == colorop->data_property)
*val = (state->data) ? state->data->base.id : 0;
+ else if (property == colorop->fixed_matrix_type_property)
+ *val = state->fixed_matrix_type;
else
return -EINVAL;

diff --git a/drivers/gpu/drm/drm_colorop.c b/drivers/gpu/drm/drm_colorop.c
index 566816e3c6f0..dd385e8dacbe 100644
--- a/drivers/gpu/drm/drm_colorop.c
+++ b/drivers/gpu/drm/drm_colorop.c
@@ -68,6 +68,7 @@ static const struct drm_prop_enum_list drm_colorop_type_enum_list[] = {
{ DRM_COLOROP_CTM_3X4, "3x4 Matrix"},
{ DRM_COLOROP_MULTIPLIER, "Multiplier"},
{ DRM_COLOROP_3D_LUT, "3D LUT"},
+ { DRM_COLOROP_FIXED_MATRIX, "Fixed Matrix"},
};

static const char * const colorop_curve_1d_type_names[] = {
@@ -90,6 +91,14 @@ static const struct drm_prop_enum_list drm_colorop_lut3d_interpolation_list[] =
{ DRM_COLOROP_LUT3D_INTERPOLATION_TETRAHEDRAL, "Tetrahedral" },
};

+static const char * const colorop_fixed_matrix_type_names[] = {
+ [DRM_COLOROP_FM_YCBCR601_FULL_RGB] = "YCbCr 601 Full to RGB",
+ [DRM_COLOROP_FM_YCBCR709_FULL_RGB] = "YCbCr 709 Full to RGB",
+ [DRM_COLOROP_FM_YCBCR2020_FULL_RGB_NC] = "YCbCr 2020 Full to RGB NC",
+ [DRM_COLOROP_FM_YCBCR_LIMITED_FULL] = "YCbCr limited to full",
+ [DRM_COLOROP_FM_RGB709_RGB2020] = "RGB709 to RGB2020",
+};
+
/* Init Helpers */

static int drm_plane_colorop_init(struct drm_device *dev, struct drm_colorop *colorop,
@@ -455,6 +464,81 @@ int drm_plane_colorop_3dlut_init(struct drm_device *dev, struct drm_colorop *col
}
EXPORT_SYMBOL(drm_plane_colorop_3dlut_init);

+/**
+ * drm_plane_colorop_fixed_matrix_init - Initialize a DRM_COLOROP_FIXED_MATRIX
+ *
+ * @dev: DRM device
+ * @colorop: The drm_colorop object to initialize
+ * @plane: The associated drm_plane
+ * @funcs: control functions for the new colorop
+ * @supported_fm: A bitfield of supported drm_colorop_fixed_matrix_type enum values,
+ * created using BIT(fixed_matrix_type) and combined with the OR '|'
+ * operator.
+ * @flags: bitmask of misc, see DRM_COLOROP_FLAG_* defines.
+ * @return zero on success, -E value on failure
+ */
+int drm_plane_colorop_fixed_matrix_init(struct drm_device *dev, struct drm_colorop *colorop,
+ struct drm_plane *plane,
+ const struct drm_colorop_funcs *funcs,
+ u64 supported_fm, uint32_t flags)
+{
+ struct drm_prop_enum_list enum_list[DRM_COLOROP_FM_COUNT];
+ int i, len;
+
+ struct drm_property *prop;
+ int ret;
+
+ if (!supported_fm) {
+ drm_err(dev,
+ "No supported FM type op for new Fixed Matrix colorop on [PLANE:%d:%s]\n",
+ plane->base.id, plane->name);
+ return -EINVAL;
+ }
+
+ if ((supported_fm & -BIT(DRM_COLOROP_FM_COUNT)) != 0) {
+ drm_err(dev, "Unknown Fixed Matrix provided on [PLANE:%d:%s]\n",
+ plane->base.id, plane->name);
+ return -EINVAL;
+ }
+
+ ret = drm_plane_colorop_init(dev, colorop, plane, funcs, DRM_COLOROP_FIXED_MATRIX, flags);
+ if (ret)
+ return ret;
+
+ len = 0;
+ for (i = 0; i < DRM_COLOROP_FM_COUNT; i++) {
+ if ((supported_fm & BIT(i)) == 0)
+ continue;
+
+ enum_list[len].type = i;
+ enum_list[len].name = colorop_fixed_matrix_type_names[i];
+ len++;
+ }
+
+ if (WARN_ON(len <= 0))
+ return -EINVAL;
+
+ prop = drm_property_create_enum(dev, DRM_MODE_PROP_ATOMIC, "FIXED_MATRIX_TYPE",
+ enum_list, len);
+
+ if (!prop)
+ return -ENOMEM;
+
+ colorop->fixed_matrix_type_property = prop;
+ /*
+ * Default to the first supported CSC mode as provided by the driver.
+ * Intuitively this should be something that keeps the colorop in pixel bypass
+ * mode but that is already handled via the standard colorop bypass
+ * property.
+ */
+ drm_object_attach_property(&colorop->base, colorop->fixed_matrix_type_property,
+ enum_list[0].type);
+ drm_colorop_reset(colorop);
+
+ return 0;
+}
+EXPORT_SYMBOL(drm_plane_colorop_fixed_matrix_init);
+
static void __drm_atomic_helper_colorop_duplicate_state(struct drm_colorop *colorop,
struct drm_colorop_state *state)
{
@@ -521,6 +605,13 @@ static void __drm_colorop_state_reset(struct drm_colorop_state *colorop_state,
&val);
colorop_state->curve_1d_type = val;
}
+
+ if (colorop->fixed_matrix_type_property) {
+ drm_object_property_get_default_value(&colorop->base,
+ colorop->fixed_matrix_type_property,
+ &val);
+ colorop_state->fixed_matrix_type = val;
+ }
}

/**
@@ -561,6 +652,7 @@ static const char * const colorop_type_name[] = {
[DRM_COLOROP_CTM_3X4] = "3x4 Matrix",
[DRM_COLOROP_MULTIPLIER] = "Multiplier",
[DRM_COLOROP_3D_LUT] = "3D LUT",
+ [DRM_COLOROP_FIXED_MATRIX] = "Fixed Matrix",
};

static const char * const colorop_lu3d_interpolation_name[] = {
@@ -617,6 +709,21 @@ const char *drm_get_colorop_lut3d_interpolation_name(enum drm_colorop_lut3d_inte
return colorop_lu3d_interpolation_name[type];
}

+/**
+ * drm_get_colorop_fixed_matrix_type_name: return a string for fixed matrix type
+ * @type: fixed matrix type to compute name of
+ *
+ * In contrast to the other drm_get_*_name functions this one here returns a
+ * const pointer and hence is threadsafe.
+ */
+const char *drm_get_colorop_fixed_matrix_type_name(enum drm_colorop_fixed_matrix_type type)
+{
+ if (WARN_ON(type >= ARRAY_SIZE(colorop_fixed_matrix_type_names)))
+ return "unknown";
+
+ return colorop_fixed_matrix_type_names[type];
+}
+
/**
* drm_colorop_set_next_property - sets the next pointer
* @colorop: drm colorop
diff --git a/include/drm/drm_colorop.h b/include/drm/drm_colorop.h
index bd082854ca74..c13b4b045fff 100644
--- a/include/drm/drm_colorop.h
+++ b/include/drm/drm_colorop.h
@@ -134,6 +134,71 @@ enum drm_colorop_curve_1d_type {
DRM_COLOROP_1D_CURVE_COUNT
};

+/**
+ * enum drm_colorop_fixed_matrix_type - type of Fixed Matrix
+ *
+ * Describes a Fixed Matrix operation to be applied by the DRM_COLOROP_FIXED_MATRIX
+ */
+enum drm_colorop_fixed_matrix_type {
+ /**
+ * @DRM_COLOROP_FM_YCBCR601_FULL_RGB:
+ *
+ * enum string "YCbCr 601 Full to RGB"
+ *
+ * This selects the matrix that converts full range YCbCr into RGB
+ * according to the BT.601 coefficients.
+ */
+ DRM_COLOROP_FM_YCBCR601_FULL_RGB,
+
+ /**
+ * @DRM_COLOROP_FM_YCBCR709_FULL_RGB:
+ *
+ * enum string "YCbCr 709 Full to RGB"
+ *
+ * This selects the matrix that converts full range YCbCr into RGB
+ * according to the BT.709 coefficients.
+ */
+ DRM_COLOROP_FM_YCBCR709_FULL_RGB,
+
+ /**
+ * @DRM_COLOROP_FM_YCBCR2020_NC_FULL_RGB:
+ *
+ * enum string "YCbCr 2020 Full to RGB NC"
+ *
+ * This selects the matrix that converts full range YCbCr into RGB
+ * according to the BT.2020 non-constant luminance coefficients.
+ */
+ DRM_COLOROP_FM_YCBCR2020_FULL_RGB_NC,
+
+ /**
+ * @DRM_COLOROP_FM_YCBCR_LIMITED_FULL:
+ *
+ * enum string "YCbCr limited to full"
+ *
+ * This selects the matrix that converts limited range YCbCr into
+ * full range YCbCr. Though not strictly a matrix operation but
+ * can be represented as one.
+ */
+ DRM_COLOROP_FM_YCBCR_LIMITED_FULL,
+
+ /**
+ * @DRM_COLOROP_FM_RGB709_RGB2020:
+ *
+ * enum string "RGB709 to RGB2020"
+ *
+ * Selects the fixed-function CSC preset that converts RGB
+ * (BT.709) colorimetry to RGB (BT.2020).
+ */
+ DRM_COLOROP_FM_RGB709_RGB2020,
+
+ /**
+ * @DRM_COLOROP_FM_COUNT:
+ *
+ * enum value denoting the size of the enum
+ */
+ DRM_COLOROP_FM_COUNT
+};
+
/**
* struct drm_colorop_state - mutable colorop state
*/
@@ -183,6 +248,13 @@ struct drm_colorop_state {
*/
struct drm_property_blob *data;

+ /**
+ * @fixed_matrix_type:
+ *
+ * Type of Fixed Matrix operation.
+ */
+ enum drm_colorop_fixed_matrix_type fixed_matrix_type;
+
/** @state: backpointer to global drm_atomic_state */
struct drm_atomic_state *state;
};
@@ -368,6 +440,13 @@ struct drm_colorop {
*/
struct drm_property *data_property;

+ /**
+ * @fixed_matrix_type_property:
+ *
+ * Sub-type for DRM_COLOROP_FIXED_MATRIX type.
+ */
+ struct drm_property *fixed_matrix_type_property;
+
/**
* @next_property:
*
@@ -424,6 +503,10 @@ int drm_plane_colorop_3dlut_init(struct drm_device *dev, struct drm_colorop *col
uint32_t lut_size,
enum drm_colorop_lut3d_interpolation_type interpolation,
uint32_t flags);
+int drm_plane_colorop_fixed_matrix_init(struct drm_device *dev, struct drm_colorop *colorop,
+ struct drm_plane *plane,
+ const struct drm_colorop_funcs *funcs,
+ u64 supported_fm, uint32_t flags);

struct drm_colorop_state *
drm_atomic_helper_colorop_duplicate_state(struct drm_colorop *colorop);
@@ -480,6 +563,7 @@ drm_get_colorop_lut1d_interpolation_name(enum drm_colorop_lut1d_interpolation_ty

const char *
drm_get_colorop_lut3d_interpolation_name(enum drm_colorop_lut3d_interpolation_type type);
+const char *drm_get_colorop_fixed_matrix_type_name(enum drm_colorop_fixed_matrix_type type);

void drm_colorop_set_next_property(struct drm_colorop *colorop, struct drm_colorop *next);

diff --git a/include/uapi/drm/drm_mode.h b/include/uapi/drm/drm_mode.h
index a4bdc4bd11bc..dc4b8566fec8 100644
--- a/include/uapi/drm/drm_mode.h
+++ b/include/uapi/drm/drm_mode.h
@@ -971,6 +971,18 @@ enum drm_colorop_type {
* color = lut3d[index]
*/
DRM_COLOROP_3D_LUT,
+
+ /**
+ * @DRM_COLOROP_FIXED_MATRIX:
+ *
+ * enum string "Fixed Matrix"
+ *
+ * A Colorop block that performs a pre-defined matrix operation selected
+ * via the FIXED_MATRIX_TYPE enum property. The driver advertises the supported
+ * operations through this property.
+ */
+ DRM_COLOROP_FIXED_MATRIX,
+
};

/**
--
2.25.1