Holding the visible_fb in the eglstreams DisplayBuffer

src/platforms/eglstream-kms/server/display.cpp

@@ -213,12 +213,11 @@ class DisplayBuffer
 
         if (next_swap) // This is the KMS route
         {
+            visible_fb = std::move(next_swap);
+            next_swap = nullptr;
             auto const predicted_render_time = 50ms; // Predicted worst case render time for the next frame...
 
-            output->queue_atomic_flip(*next_swap, event_handler->drm_event_data());
-            // TODO: Do we need to wait for a page flip here? KMS does it here,
-            // but perhaps our 'pending_flip.get()' is good enough? I am a bit unfamiliar
-            next_swap = nullptr;
+            output->queue_atomic_flip(*visible_fb, event_handler->drm_event_data());
             auto const min_frame_interval = 1000ms / output->max_refresh_rate();
             if (predicted_render_time < min_frame_interval)
                 recommend_sleep = min_frame_interval - predicted_render_time;
@@ -338,6 +337,7 @@ class DisplayBuffer
 
     /// Used only for the KMS case
     std::shared_ptr<mg::FBHandle const> next_swap{nullptr};
+    std::shared_ptr<mg::FBHandle const> visible_fb{nullptr};
     std::chrono::milliseconds recommend_sleep{0};
 };