3 files changed, 18 insertions, 2 deletions
diff --git a/src/plugins/platforms/xcb/qxcbconnection.cpp b/src/plugins/platforms/xcb/qxcbconnection.cpp
index 1b72bb0da1..7f23c84cb9 100644
--- a/src/plugins/platforms/xcb/qxcbconnection.cpp
+++ b/src/plugins/platforms/xcb/qxcbconnection.cpp
@@ -1028,6 +1028,15 @@ void QXcbEventReader::registerForEvents()
     connect(dispatcher, SIGNAL(awake()), m_connection, SLOT(processXcbEvents()));
 }
 
+void QXcbEventReader::registerEventDispatcher(QAbstractEventDispatcher *dispatcher)
+{
+    // flush the xcb connection before the EventDispatcher is going to block
+    // In the non-threaded case processXcbEvents is called before going to block,
+    // which flushes the connection.
+    if (m_xcb_poll_for_queued_event)
+        connect(dispatcher, SIGNAL(aboutToBlock()), m_connection, SLOT(flush()));
+}
+
 void QXcbEventReader::run()
 {
     xcb_generic_event_t *event;
diff --git a/src/plugins/platforms/xcb/qxcbconnection.h b/src/plugins/platforms/xcb/qxcbconnection.h
index 6c9ccbcc2f..0bfc2f8f76 100644
--- a/src/plugins/platforms/xcb/qxcbconnection.h
+++ b/src/plugins/platforms/xcb/qxcbconnection.h
@@ -311,6 +311,8 @@ public:
 
     void start();
 
+    void registerEventDispatcher(QAbstractEventDispatcher *dispatcher);
+
 signals:
     void eventPending();
 
@@ -410,7 +412,6 @@ public:
 
 
     void sync();
-    void flush() { xcb_flush(m_connection); }
 
     void handleXcbError(xcb_generic_error_t *error);
     void handleXcbEvent(xcb_generic_event_t *event);
@@ -464,8 +465,11 @@ public:
     void handleEnterEvent(const xcb_enter_notify_event_t *);
 #endif
 
+    QXcbEventReader *eventReader() const { return m_reader; }
+
 public slots:
     void syncWindow(QXcbWindow *window);
+    void flush() { xcb_flush(m_connection); }
 
 private slots:
     void processXcbEvents();
diff --git a/src/plugins/platforms/xcb/qxcbintegration.cpp b/src/plugins/platforms/xcb/qxcbintegration.cpp
index ddb164bf07..1b1c20f02c 100644
--- a/src/plugins/platforms/xcb/qxcbintegration.cpp
+++ b/src/plugins/platforms/xcb/qxcbintegration.cpp
@@ -303,7 +303,10 @@ bool QXcbIntegration::hasCapability(QPlatformIntegration::Capability cap) const
 
 QAbstractEventDispatcher *QXcbIntegration::createEventDispatcher() const
 {
-    return createUnixEventDispatcher();
+    QAbstractEventDispatcher *dispatcher = createUnixEventDispatcher();
+    for (int i = 0; i < m_connections.size(); i++)
+        m_connections[i]->eventReader()->registerEventDispatcher(dispatcher);
+    return dispatcher;
 }
 
 void QXcbIntegration::initialize()