drm/doc: Move legacy kms helpers to the very end

We don't want people to accidentally stumble over there.

Also rename the plane helpers to legacy plane helpers. After Ville's
patch to make the clipping helper atomic and move it to
drm_atomic_helper.c there's nothing left in there that should be
useful for modern drivers.

v2: Laurent had a few questions around how state is added to
drm_atomic_state, tried to clarify that. And spotted another sentence
where the docs suggested subclassing.

v3: Small polish (Alex).
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171214203054.20141-6-daniel.vetter@ffwll.ch

Documentation/gpu/drm-kms-helpers.rst

@@ -74,15 +74,6 @@ Helper Functions Reference
 .. kernel-doc:: drivers/gpu/drm/drm_atomic_helper.c
    :export:
 
-Legacy CRTC/Modeset Helper Functions Reference
-==============================================
-
-.. kernel-doc:: drivers/gpu/drm/drm_crtc_helper.c
-   :doc: overview
-
-.. kernel-doc:: drivers/gpu/drm/drm_crtc_helper.c
-   :export:
-
 Simple KMS Helper Reference
 ===========================
 
@@ -282,15 +273,6 @@ Flip-work Helper Reference
 .. kernel-doc:: drivers/gpu/drm/drm_flip_work.c
    :export:
 
-Plane Helper Reference
-======================
-
-.. kernel-doc:: drivers/gpu/drm/drm_plane_helper.c
-   :doc: overview
-
-.. kernel-doc:: drivers/gpu/drm/drm_plane_helper.c
-   :export:
-
 Auxiliary Modeset Helpers
 =========================
 
@@ -308,3 +290,21 @@ Framebuffer GEM Helper Reference
 
 .. kernel-doc:: drivers/gpu/drm/drm_gem_framebuffer_helper.c
    :export:
+
+Legacy Plane Helper Reference
+=============================
+
+.. kernel-doc:: drivers/gpu/drm/drm_plane_helper.c
+   :doc: overview
+
+.. kernel-doc:: drivers/gpu/drm/drm_plane_helper.c
+   :export:
+
+Legacy CRTC/Modeset Helper Functions Reference
+==============================================
+
+.. kernel-doc:: drivers/gpu/drm/drm_crtc_helper.c
+   :doc: overview
+
+.. kernel-doc:: drivers/gpu/drm/drm_crtc_helper.c
+   :export:

Documentation/gpu/drm-kms.rst

@@ -263,10 +263,10 @@ Taken all together there's two consequences for the atomic design:
 
 - An atomic update is assembled and validated as an entirely free-standing pile
   of structures within the :c:type:`drm_atomic_state <drm_atomic_state>`
-  container. Again drivers can subclass that container for their own state
-  structure tracking needs. Only when a state is committed is it applied to the
-  driver and modeset objects. This way rolling back an update boils down to
-  releasing memory and unreferencing objects like framebuffers.
+  container. Driver private state structures are also tracked in the same
+  structure; see the next chapter.  Only when a state is committed is it applied
+  to the driver and modeset objects. This way rolling back an update boils down
+  to releasing memory and unreferencing objects like framebuffers.
 
 Read on in this chapter, and also in :ref:`drm_atomic_helper` for more detailed
 coverage of specific topics.

include/drm/drm_atomic.h

@@ -246,6 +246,10 @@ struct __drm_private_objs_state {
  * @num_private_objs: size of the @private_objs array
  * @private_objs: pointer to array of private object pointers
  * @acquire_ctx: acquire context for this atomic modeset state update
+ *
+ * States are added to an atomic update by calling drm_atomic_get_crtc_state(),
+ * drm_atomic_get_plane_state(), drm_atomic_get_connector_state(), or for
+ * private state structures, drm_atomic_get_private_obj_state().
  */
 struct drm_atomic_state {
 	struct kref ref;