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

Harry Wentland
2026-04-30T17:28:42Z

On 2026-04-22 17:30, Melissa Wen wrote:
>
>
> On 21/04/2026 11:57, Borah, Chaitanya Kumar wrote:
>>
>>
>> On 4/21/2026 6:40 PM, Melissa Wen wrote:
>>>
>>>
>>> On 08/04/2026 02:15, Chaitanya Kumar Borah wrote:
>>>> 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"
>>> Nit: I think you mean "YCbCr 2020 NC Full to RGB"?
>>>> +     *
>>>> +     * 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,
>>> ... and here ^ DRM_COLOROP_FM_YCBCR_NC_FULL_RGB
>>
>> Ack.
>>
>>>> +
>>>> +    /**
>>>> +     * @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,
>>> I didn't full understand how this is going to work.
>>> Looks like it's merging two properties (COLOR_ENCODING and COLOR_RANGE) in a single colorop.
>>> But we can only select one enum value. So how to communicate, for example, a "YCbCr 709 Limited to RGB" conversion?
>>> The driver will have to define a coloro pipeline with two fixed matrix colorop in a row, one with only "Limited to Full" and another with "YCbCr Full to RGB" ?
>>>
>>
>> It depends on what the HW supports. Let's say a fixed function HW block can itself support "YCbCr Limited to RGB" then we just need a single colorop that exposes this enum. These are being added in the series that Harry published.[1]
>>
>> In Intel's case, we have two separate blocks to do this. One that does the range correction (Limited to Full) and then a fixed function CSC block that does only "YCbCr Full to RGB" conversion. If they are adjacent in the pipeline, they can very well be represent by a single colorop described in the previous paragraph but we have a unique situation where there is a 1D LUT in between the two blocks.
>>
>> [YUV Limited to Full] -> [1D LUT] -> [YCbCr XXX Full to RGB] -> [1D LUT].
>
> I see. Thanks for clarifying.
>
> Apart from the DRM_COLOROP_FM_YCBCR_NC_FULL_RGB fix above-mentioned, this patch LGTM.
> It was missing IGT tests, but I see Harry provided it in the series you linked.
>
> Reviewed-by: Melissa Wen <mwen@igalia.com>

Feel free to also add my
Reviewed-by: Harry Wentland <harry.wentland@amd.com>

Harry

>
>>
>> ==
>> Chaitanya
>>
>> [1] https://lore.kernel.org/dri-devel/20260330153451.99472-3-harry.wentland@amd.com/
>>
>>> Melissa
>>>> +
>>>> +    /**
>>>> +     * @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,
>>>> +
>>>>   };
>>>>   /**
>>>
>>
>