Client: Full implementation for frame callbacks

The Wayland plugin now takes full control over delivering update request and
implement frame callbacks for both egl and shm.

Fixes two bugs:

[ChangeLog][Client] The non-blocking version of eglSwapBuffers is now used.
This fixed a bug where minimized windows would block the event loop.

Also, when we relied on the QPA version of requestUpdate, we would sometimes
deliver one update request while we were waiting for a frame callback. When we
implement the fallback timer ourselves we can make sure we only deliver the
fallback if there are no pending frame callbacks.

Fixes: QTBUG-69077
Change-Id: I2d3a6896c32e63d8520b57448a3601a817816a91
Reviewed-by: Paul Olav Tvete <paul.tvete@qt.io>

1 files changed, 8 insertions, 1 deletions

diff --git a/src/client/qwaylandwindow_p.h b/src/client/qwaylandwindow_p.h
index 56ebd3cc6..e5838d231 100644
--- a/src/client/qwaylandwindow_p.h
+++ b/src/client/qwaylandwindow_p.h
@@ -191,7 +191,10 @@ public:
 
     bool startSystemMove(const QPoint &pos) override;
 
+    void timerEvent(QTimerEvent *event) override;
     void requestUpdate() override;
+    void handleUpdate();
+    void deliverUpdateRequest() override;
 
 public slots:
     void applyConfigure();
@@ -211,10 +214,14 @@ protected:
     Qt::MouseButtons mMousePressedInContentArea = Qt::NoButton;
 
     WId mWindowId;
-    bool mWaitingForFrameSync = false;
+    bool mWaitingForFrameCallback = false;
     struct ::wl_callback *mFrameCallback = nullptr;
     QWaitCondition mFrameSyncWait;
 
+    // True when we have called deliverRequestUpdate, but the client has not yet attached a new buffer
+    bool mWaitingForUpdate = false;
+    int mFallbackUpdateTimerId = -1;
+
     QMutex mResizeLock;
     bool mWaitingToApplyConfigure = false;
     bool mCanResize = true;