D3D12: Add a way to test device loss and fix discovered issues

Set QT_D3D_DEVICE_LOSS_TEST to a number N > 0 to trigger a device reset N
times in 5 second intervals.

Cinematic is able to survive now which is excellent news.

Also tested a real driver update which worked as well, Cinematic kept
running all the time (unlike Creator).

Change-Id: Ib59c7dece6b90321e6bd7e01c0687c51d5b61333
Reviewed-by: Andy Nichols <andy.nichols@qt.io>

1 files changed, 14 insertions, 0 deletions

diff --git a/src/plugins/scenegraph/d3d12/qsgd3d12renderloop.cpp b/src/plugins/scenegraph/d3d12/qsgd3d12renderloop.cpp
index 9798f0ca66..44c2744978 100644
--- a/src/plugins/scenegraph/d3d12/qsgd3d12renderloop.cpp
+++ b/src/plugins/scenegraph/d3d12/qsgd3d12renderloop.cpp
@@ -656,6 +656,20 @@ void QSGD3D12RenderThread::syncAndRender()
                int(threadTimer.elapsed() - renderTime / 1000000));
 
     Q_QUICK_SG_PROFILE_END(QQuickProfiler::SceneGraphRenderLoopFrame);
+
+    static int devLossTest = qEnvironmentVariableIntValue("QT_D3D_TEST_DEVICE_LOSS");
+    if (devLossTest > 0) {
+        static QElapsedTimer kt;
+        static bool timerRunning = false;
+        if (!timerRunning) {
+            kt.start();
+            timerRunning = true;
+        } else if (kt.elapsed() > 5000) {
+            --devLossTest;
+            kt.restart();
+            engine->simulateDeviceLoss();
+        }
+    }
 }
 
 template<class T> T *windowFor(const QVector<T> &list, QQuickWindow *window)