drm: some KMS todo ideas

Inspired by discussions with Keith and Ville.

Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Keith Packard <keithp@keithp.com>
Acked-by: Sean Paul <seanpaul@chromium.org>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171017162918.8380-1-daniel.vetter@ffwll.ch

Documentation/gpu/todo.rst

@@ -304,6 +304,18 @@ There's a bunch of issues with it:
 
 Contact: Daniel Vetter
 
+KMS cleanups
+------------
+
+Some of these date from the very introduction of KMS in 2008 ...
+
+- drm_mode_config.crtc_idr is misnamed, since it contains all KMS object. Should
+  be renamed to drm_mode_config.object_idr.
+
+- drm_display_mode doesn't need to be derived from drm_mode_object. That's
+  leftovers from older (never merged into upstream) KMS designs where modes
+  where set using their ID, including support to add/remove modes.
+
 Better Testing
 ==============