drm/amd/display: Enable DEGAMMA and reject COLOR_PIPELINE+DEGAMMA_LUT

[WHAT]
Create DEGAMMA properties even if color pipeline is enabled, and enforce
the mutual exclusion in atomic check by rejecting any commit that
attempts to enable both COLOR_PIPELINE on the plane and DEGAMMA_LUT on
the CRTC simultaneously.

Fixes: 18a4127 ("drm/amd/display: Disable CRTC degamma when color pipeline is enabled")
Closes: https://gitlab.freedesktop.org/drm/amd/-/issues/4963
Reviewed-by: Melissa Wen <mwen@igalia.com>
Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Alex Hung <alex.hung@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
(cherry picked from commit 196a6aa)

Author: Alex Hung

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_crtc.c

@@ -765,15 +765,15 @@ int amdgpu_dm_crtc_init(struct amdgpu_display_manager *dm,
 	dm->adev->mode_info.crtcs[crtc_index] = acrtc;
 
 	/* Don't enable DRM CRTC degamma property for
-	 * 1. Degamma is replaced by color pipeline.
-	 * 2. DCE since it doesn't support programmable degamma anywhere.
-	 * 3. DCN401 since pre-blending degamma LUT doesn't apply to cursor.
+	 * 1. DCE since it doesn't support programmable degamma anywhere.
+	 * 2. DCN401 since pre-blending degamma LUT doesn't apply to cursor.
+	 * Note: DEGAMMA properties are created even if the primary plane has the
+	 * COLOR_PIPELINE property. User space can use either the DEGAMMA properties
+	 * or the COLOR_PIPELINE property. An atomic commit which attempts to enable
+	 * both is rejected.
 	 */
-	if (plane->color_pipeline_property)
-		has_degamma = false;
-	else
-		has_degamma = dm->adev->dm.dc->caps.color.dpp.dcn_arch &&
-			      dm->adev->dm.dc->ctx->dce_version != DCN_VERSION_4_01;
+	has_degamma = dm->adev->dm.dc->caps.color.dpp.dcn_arch &&
+		      dm->adev->dm.dc->ctx->dce_version != DCN_VERSION_4_01;
 
 	drm_crtc_enable_color_mgmt(&acrtc->base, has_degamma ? MAX_COLOR_LUT_ENTRIES : 0,
 				   true, MAX_COLOR_LUT_ENTRIES);

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_plane.c

@@ -1256,6 +1256,14 @@ static int amdgpu_dm_plane_atomic_check(struct drm_plane *plane,
 	if (ret)
 		return ret;
 
+	/* Reject commits that attempt to use both COLOR_PIPELINE and CRTC DEGAMMA_LUT */
+	if (new_plane_state->color_pipeline && new_crtc_state->degamma_lut) {
+		drm_dbg_atomic(plane->dev,
+			       "[PLANE:%d:%s] COLOR_PIPELINE and CRTC DEGAMMA_LUT cannot be enabled simultaneously\n",
+			       plane->base.id, plane->name);
+		return -EINVAL;
+	}
+
 	ret = amdgpu_dm_plane_fill_dc_scaling_info(adev, new_plane_state, &scaling_info);
 	if (ret)
 		return ret;