1 files changed, 15 insertions, 7 deletions
diff --git a/src/hardwareintegration/client/wayland-egl/qwaylandglcontext.cpp b/src/hardwareintegration/client/wayland-egl/qwaylandglcontext.cpp
index 0cbbe5389..e58403ad0 100644
--- a/src/hardwareintegration/client/wayland-egl/qwaylandglcontext.cpp
+++ b/src/hardwareintegration/client/wayland-egl/qwaylandglcontext.cpp
@@ -315,9 +315,7 @@ QWaylandGLContext::QWaylandGLContext(EGLDisplay eglDisplay, QWaylandDisplay *dis
        mSupportNonBlockingSwap = false;
     }
     if (!mSupportNonBlockingSwap) {
-        qWarning(lcQpaWayland) << "Non-blocking swap buffers not supported."
-                               << "Subsurface rendering can be affected."
-                               << "It may also cause the event loop to freeze in some situations";
+        qWarning() << "Non-blocking swap buffers not supported. Subsurface rendering can be affected.";
     }
 
     updateGLFormat();
@@ -552,10 +550,20 @@ void QWaylandGLContext::swapBuffers(QPlatformSurface *surface)
         m_blitter->blit(window);
     }
 
-    window->handleUpdate();
-    int swapInterval = mSupportNonBlockingSwap ? 0 : m_format.swapInterval();
-    eglSwapInterval(m_eglDisplay, swapInterval);
-    eglSwapBuffers(m_eglDisplay, eglSurface);
+
+    QWaylandSubSurface *sub = window->subSurfaceWindow();
+    if (sub) {
+        QMutexLocker l(sub->syncMutex());
+
+        int si = (sub->isSync() && mSupportNonBlockingSwap) ? 0 : m_format.swapInterval();
+
+        eglSwapInterval(m_eglDisplay, si);
+        eglSwapBuffers(m_eglDisplay, eglSurface);
+    } else {
+        eglSwapInterval(m_eglDisplay, m_format.swapInterval());
+        eglSwapBuffers(m_eglDisplay, eglSurface);
+    }
+
 
     window->setCanResize(true);
 }