Fix mac build

examples/rhi/shared/examplefw.h

@@ -391,14 +391,20 @@ void Window::render()
 
     m_r->endFrame(m_sc);
 
-    // There should be no need to rely on requestUpdate().
-    // Outside Apple that's a 5 ms timer, otherwise backed by CVDisplayLink but
-    // for Metal we do not need that either.
-    bool sillyPlatform = false;
+    // There should be no need to rely on requestUpdate(). Outside Apple that's
+    // a 5 ms timer, otherwise backed by CVDisplayLink but for Metal we do not
+    // need that either, on macOS at least. For iOS/tvOS however, or when using
+    // OpenGL on Apple, continue to use requestUpdate.
+    bool useRequestUpdate = false;
 #ifdef Q_OS_DARWIN
-    sillyPlatform = graphicsApi == OpenGL;
+#if defined(Q_OS_IOS) || defined(Q_OS_TVOS)
+    useRequestUpdate = true;
+#else
+    if (graphicsApi == OpenGL)
+        useRequestUpdate = true;
+#endif
 #endif
-    if (sillyPlatform)
+    if (useRequestUpdate)
         requestUpdate();
     else
         QCoreApplication::postEvent(this, new QEvent(QEvent::UpdateRequest));

src/rhi/qrhid3d11.cpp

@@ -567,9 +567,11 @@ QRhi::FrameOpResult QRhiD3D11::beginFrame(QRhiSwapChain *swapChain)
         ok &= context->GetData(tsStart, &timestamps[0], sizeof(quint64), D3D11_ASYNC_GETDATA_DONOTFLUSH) == S_OK;
         if (ok) {
             if (!dj.Disjoint && dj.Frequency) {
-                // The timestamps seem to include vsync time with Present(1) on
-                // AMD and Intel, but not with NVIDIA. The latter is what we
-                // would need but not much we can do about it.
+                // The timestamps seem to include vsync time with Present(1),
+                // except when running on a non-primary gpu. This is not ideal,
+                // and differs from other backends (Vulkan), but not much we
+                // can do about it. (apart from telling people to set NoVSync
+                // to get more useful results)
                 const float elapsedMs = (timestamps[1] - timestamps[0]) / float(dj.Frequency) * 1000.0f;
 
                 // finally got a value, just report it, the profiler cares about min/max/avg anyway

src/rhi/qrhimetal.mm

@@ -2557,8 +2557,12 @@ bool QMetalSwapChain::buildOrResize()
     if (m_flags.testFlag(UsedAsTransferSource))
         d->layer.framebufferOnly = NO;
 
-    if (m_flags.testFlag(NoVSync))
+#ifdef Q_OS_MAC
+    if (m_flags.testFlag(NoVSync)) {
+        if (@available(macOS 10.13, *))
             d->layer.displaySyncEnabled = NO;
+    }
+#endif
 
     m_currentPixelSize = surfacePixelSize();
     pixelSize = m_currentPixelSize;