drm/doc: Improve docs for conn_state->best_encoder
It's mandatory and considered core state since ioctls rely on this
working.
Thanks to Laurent for pointing out this gap.
v2: Clarify to "atomic drivers" only.
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Sean Paul <sean@poorly.run>
Acked-by: Sean Paul <sean@poorly.run>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190506144629.5976-1-daniel.vetter@ffwll.ch
diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h
index 02a1312..f43f40d 100644
--- a/include/drm/drm_connector.h
+++ b/include/drm/drm_connector.h
@@ -517,6 +517,10 @@ struct drm_connector_state {
* Used by the atomic helpers to select the encoder, through the
* &drm_connector_helper_funcs.atomic_best_encoder or
* &drm_connector_helper_funcs.best_encoder callbacks.
+ *
+ * NOTE: Atomic drivers must fill this out (either themselves or through
+ * helpers), for otherwise the GETCONNECTOR and GETENCODER IOCTLs will
+ * not return correct data to userspace.
*/
struct drm_encoder *best_encoder;
