Add debug flag to enable overlay planes

src/backend/tty.rs

@@ -542,8 +542,13 @@ impl Tty {
         });
 
         let mut planes = surface.planes().clone();
-        // Disable overlay planes as they cause weird performance issues on my system.
-        planes.overlay.clear();
+
+        // Overlay planes are disabled by default as they cause weird performance issues on my
+        // system.
+        if !self.config.borrow().debug.enable_overlay_planes {
+            planes.overlay.clear();
+        }
+
         let scanout_formats = planes
             .primary
             .formats

src/config.rs

@@ -134,6 +134,8 @@ pub struct DebugConfig {
     pub wait_for_frame_completion_before_queueing: bool,
     #[knuffel(child)]
     pub enable_color_transformations_capability: bool,
+    #[knuffel(child)]
+    pub enable_overlay_planes: bool,
 }
 
 impl Default for DebugConfig {
@@ -143,6 +145,7 @@ impl Default for DebugConfig {
             screen_cast_in_non_session_instances: false,
             wait_for_frame_completion_before_queueing: false,
             enable_color_transformations_capability: false,
+            enable_overlay_planes: false,
         }
     }
 }