config: allow disabling explicit-sync

src/compositor.rs

@@ -224,6 +224,7 @@ fn start_compositor2(
         create_default_seat: Cell::new(true),
         subsurface_ids: Default::default(),
         wait_for_sync_obj: Rc::new(WaitForSyncObj::new(&ring, &engine)),
+        explicit_sync_enabled: Cell::new(true),
     });
     state.tracker.register(ClientId::from_raw(0));
     create_dummy_output(&state);

src/config/handler.rs

@@ -800,6 +800,10 @@ impl ConfigProxyHandler {
         self.state.idle.set_timeout(timeout);
     }
 
+    fn handle_set_explicit_sync_enabled(&self, enabled: bool) {
+        self.state.explicit_sync_enabled.set(enabled);
+    }
+
     fn handle_connector_connected(&self, connector: Connector) -> Result<(), CphError> {
         let connector = self.get_connector(connector)?;
         self.respond(Response::ConnectorConnected {
@@ -1725,6 +1729,9 @@ impl ConfigProxyHandler {
             } => self
                 .handle_move_to_output(workspace, connector)
                 .wrn("move_to_output")?,
+            ClientMessage::SetExplicitSyncEnabled { enabled } => {
+                self.handle_set_explicit_sync_enabled(enabled)
+            }
         }
         Ok(())
     }

src/state.rs

@@ -172,6 +172,7 @@ pub struct State {
     pub create_default_seat: Cell<bool>,
     pub subsurface_ids: SubsurfaceIds,
     pub wait_for_sync_obj: Rc<WaitForSyncObj>,
+    pub explicit_sync_enabled: Cell<bool>,
 }
 
 // impl Drop for State {
@@ -450,7 +451,7 @@ impl State {
             if !self.render_ctx_ever_initialized.replace(true) {
                 self.add_global(&Rc::new(WlDrmGlobal::new(self.globals.name())));
                 self.add_global(&Rc::new(ZwpLinuxDmabufV1Global::new(self.globals.name())));
-                if ctx.sync_obj_ctx().supports_async_wait() {
+                if ctx.sync_obj_ctx().supports_async_wait() && self.explicit_sync_enabled.get() {
                     self.add_global(&Rc::new(WpLinuxDrmSyncobjManagerV1Global::new(
                         self.globals.name(),
                     )));