Compositor: Call eglUnbindWaylandDisplayWL when destroying the compositor

If unbind is not called, some drivers may try to do cleanup that depends on a
valid wl_display in eglTerminate. Arguably, this could/should also have been
fixed in the affected drivers. There is a display_destroy signal that the
driver should listen to, to avoid using dangling wl_display and wl_global
pointers.

However, by using eglUnbindWaylandDisplayWL we can force the cleanup to happen
before wl_display_destroy. Which is what this patch does.

Change-Id: Id9062de896b723838bcecac3902031e6b172a6de
Reviewed-by: Paul Olav Tvete <paul.tvete@qt.io>
Reviewed-by: Pier Luigi Fiorini <pierluigi.fiorini@liri.io>

2 files changed, 11 insertions, 0 deletions

diff --git a/src/compositor/compositor_api/qwaylandcompositor.cpp b/src/compositor/compositor_api/qwaylandcompositor.cpp
index 173b50ce0..a0d69c52e 100644
--- a/src/compositor/compositor_api/qwaylandcompositor.cpp
+++ b/src/compositor/compositor_api/qwaylandcompositor.cpp
@@ -243,6 +243,9 @@ QWaylandCompositorPrivate::~QWaylandCompositorPrivate()
     delete data_device_manager;
 #endif
 
+    // Some client buffer integrations need to clean up before the destroying the wl_display
+    client_buffer_integration.reset();
+
     wl_display_destroy(display);
 }
 
diff --git a/src/hardwareintegration/compositor/wayland-egl/waylandeglclientbufferintegration.cpp b/src/hardwareintegration/compositor/wayland-egl/waylandeglclientbufferintegration.cpp
index 2cadf8503..88dab2ab2 100644
--- a/src/hardwareintegration/compositor/wayland-egl/waylandeglclientbufferintegration.cpp
+++ b/src/hardwareintegration/compositor/wayland-egl/waylandeglclientbufferintegration.cpp
@@ -186,6 +186,7 @@ public:
     EGLDisplay egl_display = EGL_NO_DISPLAY;
     bool valid = false;
     bool display_bound = false;
+    ::wl_display *wlDisplay = nullptr;
     QOffscreenSurface *offscreenSurface = nullptr;
     QOpenGLContext *localContext = nullptr;
     QVector<QOpenGLTexture *> orphanedTextures;
@@ -394,6 +395,12 @@ WaylandEglClientBufferIntegration::WaylandEglClientBufferIntegration()
 WaylandEglClientBufferIntegration::~WaylandEglClientBufferIntegration()
 {
     WaylandEglClientBufferIntegrationPrivate::shuttingDown = true;
+    Q_D(WaylandEglClientBufferIntegration);
+    if (d->egl_unbind_wayland_display && d->display_bound) {
+        Q_ASSERT(d->wlDisplay);
+        if (!d->egl_unbind_wayland_display(d->egl_display, d->wlDisplay))
+            qWarning() << "Qt Wayland Compositor: eglUnbindWaylandDisplayWL failed";
+    }
 }
 
 void WaylandEglClientBufferIntegration::initializeHardware(struct wl_display *display)
@@ -450,6 +457,7 @@ void WaylandEglClientBufferIntegration::initializeHardware(struct wl_display *di
                 qWarning("QtCompositor: Could not bind Wayland display. Ignoring.");
             }
         }
+        d->wlDisplay = display;
     }
 
     d->funcs = new QEGLStreamConvenience;