drm/atomic: Document __drm_crtcs_state state pointer

While the old and new state pointers are somewhat self-explanatory, the
state pointer and its relation to the other two really isn't.

Now that we've cleaned up everything and it isn't used in any
modesetting path, we can document what it's still useful for: to free
the right state when we free the global state.

Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://lore.kernel.org/r/20250930-drm-no-more-existing-state-v5-36-eeb9e1287907@kernel.org
Signed-off-by: Maxime Ripard <mripard@kernel.org>

diff --git a/include/drm/drm_atomic.h b/include/drm/drm_atomic.h
index f53a32688b33fb0f629595cb0a2ac09d359f515a..6b634b7474900d0d2bc51bd645ccedf718a1cb02 100644 (file)
--- a/include/drm/drm_atomic.h
+++ b/include/drm/drm_atomic.h
@@ -180,7 +180,23 @@ struct __drm_planes_state {
 
 struct __drm_crtcs_state {
        struct drm_crtc *ptr;
-       struct drm_crtc_state *state, *old_state, *new_state;
+
+       /**
+        * @state:
+        *
+        * Used to track the @drm_crtc_state we will need to free when
+        * tearing down the associated &drm_atomic_state in
+        * $drm_mode_config_funcs.atomic_state_clear or
+        * drm_atomic_state_default_clear().
+        *
+        * Before a commit, and the call to
+        * drm_atomic_helper_swap_state() in particular, it points to
+        * the same state than @new_state. After a commit, it points to
+        * the same state than @old_state.
+        */
+       struct drm_crtc_state *state;
+
+       struct drm_crtc_state *old_state, *new_state;
 
        /**
         * @commit: