[RFC PATCH v3 17/23] drm/colorop: Introduce DRM_CLIENT_CAP_PLANE_COLOR_PIPELINE

[Harry Wentland <harry.wentland@xxxxxxx>]

With the introduction of the pre-blending color pipeline we
can no longer have color operations that don't have a clear
position in the color pipeline. We deprecate all existing
plane properties. For upstream drivers those are:
 - COLOR_ENCODING
 - COLOR_RANGE

Userspace that registers with the
DRM_CLIENT_CAP_PLANE_COLOR_PIPELINE will be permitted to set
the COLOR_PIPELINE plane property and drm_colorop properties.
But it won't be allowed to set COLOR_ENCODING and
COLOR_RANGE. Userspace that does not set this client cap
will not be permitted to touch the color pipeline.

Signed-off-by: Harry Wentland <harry.wentland@xxxxxxx>
---
 drivers/gpu/drm/drm_atomic_uapi.c | 23 ++++++++++++++++++++++-
 drivers/gpu/drm/drm_ioctl.c       |  7 +++++++
 include/drm/drm_file.h            |  7 +++++++
 include/uapi/drm/drm.h            | 15 +++++++++++++++
 4 files changed, 51 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/drm_atomic_uapi.c b/drivers/gpu/drm/drm_atomic_uapi.c
index c6629fdaa114..69c56982e2d0 100644
--- a/drivers/gpu/drm/drm_atomic_uapi.c
+++ b/drivers/gpu/drm/drm_atomic_uapi.c
@@ -610,10 +610,26 @@ static int drm_atomic_plane_set_property(struct drm_plane *plane,
 	} else if (property == plane->zpos_property) {
 		state->zpos = val;
 	} else if (property == plane->color_encoding_property) {
+		if (file_priv->plane_color_pipeline) {
+			drm_dbg_atomic(dev,
+				       "Setting COLOR_PIPELINE plane property not permitted when DRM_CLIENT_CAP_PLANE_COLOR_PIPELINE is set\n");
+			return -EINVAL;
+		}
 		state->color_encoding = val;
 	} else if (property == plane->color_range_property) {
+		if (file_priv->plane_color_pipeline) {
+			drm_dbg_atomic(dev,
+				       "Setting COLOR_PIPELINE plane property not permitted when DRM_CLIENT_CAP_PLANE_COLOR_PIPELINE is set\n");
+			return -EINVAL;
+		}
 		state->color_range = val;
 	} else if (property == plane->color_pipeline_property) {
+		if (!file_priv->plane_color_pipeline) {
+			drm_dbg_atomic(dev,
+				       "Setting COLOR_PIPELINE plane property not permitted unless DRM_CLIENT_CAP_PLANE_COLOR_PIPELINE is set\n");
+			return -EINVAL;
+		}
+
 		/* find DRM colorop object */
 		struct drm_colorop *colorop = NULL;
 		colorop = drm_colorop_find(dev, file_priv, val);
@@ -1158,6 +1174,12 @@ int drm_atomic_set_property(struct drm_atomic_state *state,
 		break;
 	}
 	case DRM_MODE_OBJECT_COLOROP: {
+		if (!file_priv->plane_color_pipeline) {
+			drm_dbg_atomic(prop->dev,
+				       "[OBJECT:%d] is a colorop but DRM_CLIENT_CAP_PLANE_COLOR_PIPELINE not set\n",
+				       obj->id);
+			ret = -EINVAL;
+		}
 		struct drm_colorop *colorop = obj_to_colorop(obj);
 		struct drm_colorop_state *colorop_state;
 
@@ -1170,7 +1192,6 @@ int drm_atomic_set_property(struct drm_atomic_state *state,
 		ret = drm_atomic_colorop_set_property(colorop,
 				colorop_state, file_priv,
 				prop, prop_value);
-
 		break;
 	}
 	default:
diff --git a/drivers/gpu/drm/drm_ioctl.c b/drivers/gpu/drm/drm_ioctl.c
index 44fda68c28ae..0d869658e13e 100644
--- a/drivers/gpu/drm/drm_ioctl.c
+++ b/drivers/gpu/drm/drm_ioctl.c
@@ -361,6 +361,13 @@ drm_setclientcap(struct drm_device *dev, void *data, struct drm_file *file_priv)
 			return -EINVAL;
 		file_priv->writeback_connectors = req->value;
 		break;
+	case DRM_CLIENT_CAP_PLANE_COLOR_PIPELINE:
+		if (!file_priv->atomic)
+			return -EINVAL;
+		if (req->value > 1)
+			return -EINVAL;
+		file_priv->plane_color_pipeline = req->value;
+		break;
 	default:
 		return -EINVAL;
 	}
diff --git a/include/drm/drm_file.h b/include/drm/drm_file.h
index e1b5b4282f75..bf11b646c898 100644
--- a/include/drm/drm_file.h
+++ b/include/drm/drm_file.h
@@ -204,6 +204,13 @@ struct drm_file {
 	 */
 	bool writeback_connectors;
 
+	/**
+	 * @plane_color_pipeline:
+	 *
+	 * True if client understands plane color pipelines
+	 */
+	bool plane_color_pipeline;
+
 	/**
 	 * @was_master:
 	 *
diff --git a/include/uapi/drm/drm.h b/include/uapi/drm/drm.h
index 841d393fb84e..2576b170e8d0 100644
--- a/include/uapi/drm/drm.h
+++ b/include/uapi/drm/drm.h
@@ -842,6 +842,21 @@ struct drm_get_cap {
  */
 #define DRM_CLIENT_CAP_WRITEBACK_CONNECTORS	5
 
+/**
+ * DRM_CLIENT_CAP_PLANE_COLOR_PIPELINE
+ *
+ * If set to 1, the DRM core will
+ * - expose plane COLOR_PIPELINE properties for pre-blending color management.
+ * - reject setting of these plane properties:
+ *   - COLOR_ENCODING
+ *   - COLOR_RANGE
+ *
+ * The client must enable &DRM_CLIENT_CAP_ATOMIC first.
+ *
+ * This capability is currently in development.
+ */
+#define DRM_CLIENT_CAP_PLANE_COLOR_PIPELINE	7
+
 /* DRM_IOCTL_SET_CLIENT_CAP ioctl argument type */
 struct drm_set_client_cap {
 	__u64 capability;
-- 
2.42.1