Hello Harry,

On 3/30/2026 9:04 PM, Harry Wentland wrote:
From: Chaitanya Kumar Borah <[email protected]>

Introduce DRM_COLOROP_CSC_FF, a new colorop type representing a
fixed-function Color Space Conversion (CSC) block.

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


Thank you for incorporating this into your series. I believe this approach should work for both Intel and AMD hardware. I've posted a v2[1] of the patch addressing Pekka's comments. Please let me know if it looks good.

==
Chaitanya

[1] https://patchwork.freedesktop.org/patch/716856/?series=162787&rev=2

Signed-off-by: Chaitanya Kumar Borah <[email protected]>
---
  drivers/gpu/drm/drm_atomic.c      |   4 ++
  drivers/gpu/drm/drm_atomic_uapi.c |   4 ++
  drivers/gpu/drm/drm_colorop.c     | 105 ++++++++++++++++++++++++++++++
  include/drm/drm_colorop.h         |  72 ++++++++++++++++++++
  include/uapi/drm/drm_mode.h       |  13 ++++
  5 files changed, 198 insertions(+)

diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c
index 41c57063f3b4..5bff85576e6b 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_CSC_FF:
+               drm_printf(p, "\tcsc_ff_type=%s\n",
+                          
drm_get_colorop_csc_ff_type_name(state->csc_ff_type));
+               break;
        default:
                break;
        }
diff --git a/drivers/gpu/drm/drm_atomic_uapi.c 
b/drivers/gpu/drm/drm_atomic_uapi.c
index 5bd5bf6661df..39b0dd1ec348 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->csc_ff_type_property) {
+               state->csc_ff_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->csc_ff_type_property)
+               *val = state->csc_ff_type;
        else
                return -EINVAL;
diff --git a/drivers/gpu/drm/drm_colorop.c b/drivers/gpu/drm/drm_colorop.c
index 566816e3c6f0..6a345e2e8b15 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_CSC_FF, "CSC Fixed-Function"},
  };
static const char * const colorop_curve_1d_type_names[] = {
@@ -90,6 +91,13 @@ static const struct drm_prop_enum_list 
drm_colorop_lut3d_interpolation_list[] =
        { DRM_COLOROP_LUT3D_INTERPOLATION_TETRAHEDRAL, "Tetrahedral" },
  };
+static const char * const colorop_csc_ff_type_names[] = {
+       [DRM_COLOROP_CSC_FF_YUV601_RGB601]   = "YUV601 to RGB601",
+       [DRM_COLOROP_CSC_FF_YUV709_RGB709]   = "YUV709 to RGB709",
+       [DRM_COLOROP_CSC_FF_YUV2020_RGB2020] = "YUV2020 to RGB2020",
+       [DRM_COLOROP_CSC_FF_RGB709_RGB2020]  = "RGB709 to RGB2020",
+};
+
  /* Init Helpers */
static int drm_plane_colorop_init(struct drm_device *dev, struct drm_colorop *colorop,
@@ -455,6 +463,80 @@ int drm_plane_colorop_3dlut_init(struct drm_device *dev, 
struct drm_colorop *col
  }
  EXPORT_SYMBOL(drm_plane_colorop_3dlut_init);
+/**
+ * drm_plane_colorop_csc_ff_init - Initialize a DRM_COLOROP_CSC_FF
+ *
+ * @dev: DRM device
+ * @colorop: The drm_colorop object to initialize
+ * @plane: The associated drm_plane
+ * @funcs: control functions for the new colorop
+ * @supported_csc_ff: A bitfield of supported drm_plane_colorop_csc_ff_type 
enum values,
+ *                    created using BIT(csc_ff_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_csc_ff_init(struct drm_device *dev, struct drm_colorop 
*colorop,
+                                 struct drm_plane *plane, const struct 
drm_colorop_funcs *funcs,
+                                 u64 supported_csc_ff, uint32_t flags)
+{
+       struct drm_prop_enum_list enum_list[DRM_COLOROP_CSC_FF_COUNT];
+       int i, len;
+
+       struct drm_property *prop;
+       int ret;
+
+       if (!supported_csc_ff) {
+               drm_err(dev,
+                       "No supported CSC op for new CSC FF colorop on 
[PLANE:%d:%s]\n",
+                       plane->base.id, plane->name);
+               return -EINVAL;
+       }
+
+       if ((supported_csc_ff & -BIT(DRM_COLOROP_CSC_FF_COUNT)) != 0) {
+               drm_err(dev, "Unknown CSC provided on [PLANE:%d:%s]\n",
+                       plane->base.id, plane->name);
+               return -EINVAL;
+       }
+
+       ret = drm_plane_colorop_init(dev, colorop, plane, funcs, 
DRM_COLOROP_CSC_FF, flags);
+       if (ret)
+               return ret;
+
+       len = 0;
+       for (i = 0; i < DRM_COLOROP_CSC_FF_COUNT; i++) {
+               if ((supported_csc_ff & BIT(i)) == 0)
+                       continue;
+
+               enum_list[len].type = i;
+               enum_list[len].name = colorop_csc_ff_type_names[i];
+               len++;
+       }
+
+       if (WARN_ON(len <= 0))
+               return -EINVAL;
+
+       prop = drm_property_create_enum(dev, DRM_MODE_PROP_ATOMIC, 
"CSC_FF_TYPE",
+                                       enum_list, len);
+
+       if (!prop)
+               return -ENOMEM;
+
+       colorop->csc_ff_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->csc_ff_type_property,
+                                  enum_list[0].type);
+       drm_colorop_reset(colorop);
+
+       return 0;
+}
+EXPORT_SYMBOL(drm_plane_colorop_csc_ff_init);
+
  static void __drm_atomic_helper_colorop_duplicate_state(struct drm_colorop 
*colorop,
                                                        struct 
drm_colorop_state *state)
  {
@@ -521,6 +603,13 @@ static void __drm_colorop_state_reset(struct 
drm_colorop_state *colorop_state,
                                                      &val);
                colorop_state->curve_1d_type = val;
        }
+
+       if (colorop->csc_ff_type_property) {
+               drm_object_property_get_default_value(&colorop->base,
+                                                     
colorop->csc_ff_type_property,
+                                                     &val);
+               colorop_state->csc_ff_type = val;
+       }
  }
/**
@@ -561,6 +650,7 @@ 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_CSC_FF] = "CSC Fixed-Function",
  };
static const char * const colorop_lu3d_interpolation_name[] = {
@@ -617,6 +707,21 @@ const char *drm_get_colorop_lut3d_interpolation_name(enum 
drm_colorop_lut3d_inte
        return colorop_lu3d_interpolation_name[type];
  }
+/**
+ * drm_get_colorop_csc_ff_type_name: return a string for interpolation type
+ * @type: csc ff 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_csc_ff_type_name(enum drm_colorop_csc_ff_type type)
+{
+       if (WARN_ON(type >= ARRAY_SIZE(colorop_csc_ff_type_names)))
+               return "unknown";
+
+       return colorop_csc_ff_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..2cd8e0779c2a 100644
--- a/include/drm/drm_colorop.h
+++ b/include/drm/drm_colorop.h
@@ -134,6 +134,60 @@ enum drm_colorop_curve_1d_type {
        DRM_COLOROP_1D_CURVE_COUNT
  };
+/**
+ * enum drm_colorop_csc_ff_type - type of CSC Fixed-Function
+ *
+ * Describes a CSC operation to be applied by the DRM_COLOROP_CSC_FF colorop.
+ */
+enum drm_colorop_csc_ff_type {
+       /**
+        * @DRM_COLOROP_CSC_FF_YUV601_RGB601
+        *
+        * enum string "YUV601 to RGB601"
+        *
+        * Selects the fixed-function CSC preset that converts YUV
+        * (BT.601) colorimetry to RGB (BT.601).
+        */
+       DRM_COLOROP_CSC_FF_YUV601_RGB601,
+
+       /**
+        * @DRM_COLOROP_CSC_FF_YUV709_RGB709:
+        *
+        * enum string "YUV709 to RGB709"
+        *
+        * Selects the fixed-function CSC preset that converts YUV
+        * (BT.709) colorimetry to RGB (BT.709).
+        */
+       DRM_COLOROP_CSC_FF_YUV709_RGB709,
+
+       /**
+        * @DRM_COLOROP_CSC_FF_YUV2020_RGB2020:
+        *
+        * enum string "YUV2020 to RGB2020"
+        *
+        * Selects the fixed-function CSC preset that converts YUV
+        * (BT.2020) colorimetry to RGB (BT.2020).
+        */
+       DRM_COLOROP_CSC_FF_YUV2020_RGB2020,
+
+       /**
+        * @DRM_COLOROP_CSC_FF_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_CSC_FF_RGB709_RGB2020,
+
+       /**
+        * @DRM_COLOROP_CSC_FF_COUNT:
+        *
+        * enum value denoting the size of the enum
+        */
+       DRM_COLOROP_CSC_FF_COUNT
+};
+
  /**
   * struct drm_colorop_state - mutable colorop state
   */
@@ -183,6 +237,13 @@ struct drm_colorop_state {
         */
        struct drm_property_blob *data;
+ /**
+        * @csc_ff_type:
+        *
+        * Type of Fixed function CSC.
+        */
+       enum drm_colorop_csc_ff_type csc_ff_type;
+
        /** @state: backpointer to global drm_atomic_state */
        struct drm_atomic_state *state;
  };
@@ -368,6 +429,13 @@ struct drm_colorop {
         */
        struct drm_property *data_property;
+ /**
+        * @csc_ff_type_property:
+        *
+        * Sub-type for DRM_COLOROP_CSC_FF type.
+        */
+       struct drm_property *csc_ff_type_property;
+
        /**
         * @next_property:
         *
@@ -424,6 +492,9 @@ 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_csc_ff_init(struct drm_device *dev, struct drm_colorop 
*colorop,
+                                 struct drm_plane *plane, const struct 
drm_colorop_funcs *funcs,
+                                 u64 supported_csc_ff, uint32_t flags);
struct drm_colorop_state *
  drm_atomic_helper_colorop_duplicate_state(struct drm_colorop *colorop);
@@ -480,6 +551,7 @@ 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_csc_ff_type_name(enum drm_colorop_csc_ff_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..5d21f73c3d76 100644
--- a/include/uapi/drm/drm_mode.h
+++ b/include/uapi/drm/drm_mode.h
@@ -971,6 +971,19 @@ enum drm_colorop_type {
         *         color = lut3d[index]
         */
        DRM_COLOROP_3D_LUT,
+
+       /**
+        * @DRM_COLOROP_CSC_FF:
+        *
+        * enum string "CSC Fixed-Function"
+        *
+        * A fixed-function Color Space Conversion block where the coefficients
+        * are not programmable but selected from predefined hardware modes via
+        * the CSC_FF_TYPE enum property. The driver advertises the supported
+        * CSC modes through this property.
+        */
+       DRM_COLOROP_CSC_FF,
+
  };
/**

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