Re: [PATCH v4 08/11] drm/amd/display: Use GAMCOR for first TF if YUV conversion is needed

Hi, as per my previous comment:

Tested-by: Robert Mader <[email protected]>

On 22.07.26 15:46, Harry Wentland wrote:
> For subsampled formats we need to use GAMCOR instead of
> the DEGAM block. The color module can create a LUT for
> that if we set map_user_ramp to true. So do that when
> we have subsampled formats.
>
> Assisted-by: Claude:claude-sonnet-4.5
> Signed-off-by: Harry Wentland <[email protected]>
> ---
>   .../drm/amd/display/amdgpu_dm/amdgpu_dm_color.c | 17 ++++++++++++++++-
>   1 file changed, 16 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_color.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_color.c
> index 62791077ceef..8913bc9f0f06 100644
> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_color.c
> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_color.c
> @@ -1524,6 +1524,8 @@ __set_colorop_in_tf_1d_curve(struct dc_plane_state *dc_plane_state,
>   	struct dc_transfer_func *tf = &dc_plane_state->in_transfer_func;
>   	struct drm_colorop *colorop = colorop_state->colorop;
>   	struct drm_device *drm = colorop->dev;
> +	struct dc_color_caps *color_caps = NULL;
> +	bool is_subsampled_format;
>   
>   	if (colorop->type != DRM_COLOROP_1D_CURVE)
>   		return -EINVAL;
> @@ -1537,10 +1539,23 @@ __set_colorop_in_tf_1d_curve(struct dc_plane_state *dc_plane_state,
>   	}
>   
>   	drm_dbg(drm, "Degamma colorop with ID: %d\n", colorop->base.id);
> -
>   	tf->type = TF_TYPE_PREDEFINED;
> +
> +	/* Check if format requires post-scale color processing (subsampled formats) */
> +	is_subsampled_format = (dc_plane_state->format >= SURFACE_PIXEL_FORMAT_VIDEO_BEGIN &&
> +				dc_plane_state->format < SURFACE_PIXEL_FORMAT_SUBSAMPLE_END);
> +
>   	tf->tf = amdgpu_colorop_tf_to_dc_tf(colorop_state->curve_1d_type);
>   
> +	if (dc_plane_state->ctx && dc_plane_state->ctx->dc)
> +		color_caps = &dc_plane_state->ctx->dc->caps.color;
> +
> +	if (!mod_color_calculate_degamma_params(color_caps, tf, NULL,
> +						is_subsampled_format)) {
> +		drm_err(drm, "Failed to calculate degamma params\n");
> +		return -EINVAL;
> +	}
> +
>   	return 0;
>   }
>   EXPORT_IF_KUNIT(__set_colorop_in_tf_1d_curve);

-- 
Robert Mader
Consultant Software Developer

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