Client: Send subsurface expose event when toplevel is configured

If a subsurface is set to be visible on the cilent side before the top
level is configured it will do not create an exposeEvent and map a
buffer as we fail the check in isExposed() where we check the parent.
This is correct behavior.

However, when the toplevel receives an applyConfigure from the shell
client we need subsurfaces to update accordingly.

This fixes a race where subsurfaces are not shown with slow compositors.

Change-Id: Icd156e7655d5b25535acc4d2fe77c31e19ebfa32
Fixes: QTBUG-86176
Reviewed-by: David Edmundson <davidedmundson@kde.org>
(cherry picked from commit e20e1d506d627a53d9d7bf7794b93bf9e8b9bedb)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

2 files changed, 14 insertions, 1 deletions

diff --git a/src/client/qwaylandwindow.cpp b/src/client/qwaylandwindow.cpp
index 2e0614ec9..7c2815f68 100644
--- a/src/client/qwaylandwindow.cpp
+++ b/src/client/qwaylandwindow.cpp
@@ -518,10 +518,22 @@ void QWaylandWindow::applyConfigure()
         doApplyConfigure();
 
     lock.unlock();
-    sendExposeEvent(QRect(QPoint(), geometry().size()));
+    sendRecursiveExposeEvent();
     QWindowSystemInterface::flushWindowSystemEvents();
 }
 
+void QWaylandWindow::sendRecursiveExposeEvent()
+{
+    if (!window()->isVisible())
+        return;
+    sendExposeEvent(QRect(QPoint(), geometry().size()));
+
+    for (QWaylandSubSurface *subSurface : qAsConst(mChildren)) {
+        auto subWindow = subSurface->window();
+        subWindow->sendRecursiveExposeEvent();
+    }
+}
+
 void QWaylandWindow::attach(QWaylandBuffer *buffer, int x, int y)
 {
     Q_ASSERT(!buffer->committed());
diff --git a/src/client/qwaylandwindow_p.h b/src/client/qwaylandwindow_p.h
index be06e435f..948e0ea7a 100644
--- a/src/client/qwaylandwindow_p.h
+++ b/src/client/qwaylandwindow_p.h
@@ -271,6 +271,7 @@ private:
 
     void handleMouseEventWithDecoration(QWaylandInputDevice *inputDevice, const QWaylandPointerEvent &e);
     void handleScreensChanged();
+    void sendRecursiveExposeEvent();
 
     bool mInResizeFromApplyConfigure = false;
     bool lastVisible = false;