Merge remote-tracking branch 'origin/5.15' into dev

Change-Id: Ideaa64d583746f1ce8265997131fb1ce3a9acbcf

8 files changed, 214 insertions, 333 deletions

diff --git a/src/plugins/platforms/android/qandroidplatformtheme.cpp b/src/plugins/platforms/android/qandroidplatformtheme.cpp
index 7fc68c3d7c..d3a8a53241 100644
--- a/src/plugins/platforms/android/qandroidplatformtheme.cpp
+++ b/src/plugins/platforms/android/qandroidplatformtheme.cpp
@@ -465,7 +465,8 @@ QVariant QAndroidPlatformTheme::themeHint(ThemeHint hint) const
             return QStringList(QLatin1String("android"));
         }
         return QStringList(QLatin1String("fusion"));
-
+    case DialogButtonBoxLayout:
+        return QVariant(QPlatformDialogHelper::AndroidLayout);
     case MouseDoubleClickDistance:
     {
             int minimumDistance = qEnvironmentVariableIntValue("QT_ANDROID_MINIMUM_MOUSE_DOUBLE_CLICK_DISTANCE");
@@ -489,8 +490,6 @@ QVariant QAndroidPlatformTheme::themeHint(ThemeHint hint) const
 
             Q_FALLTHROUGH();
     }
-    case DialogButtonBoxLayout:
-        return QVariant(QPlatformDialogHelper::AndroidLayout);
     default:
         return QPlatformTheme::themeHint(hint);
     }
diff --git a/src/plugins/platforms/cocoa/qcocoaeventdispatcher.mm b/src/plugins/platforms/cocoa/qcocoaeventdispatcher.mm
index d3bb0711f0..e87fc39c42 100644
--- a/src/plugins/platforms/cocoa/qcocoaeventdispatcher.mm
+++ b/src/plugins/platforms/cocoa/qcocoaeventdispatcher.mm
@@ -881,7 +881,7 @@ void QCocoaEventDispatcherPrivate::processPostedEvents()
         return;
     }
 
-    int serial = serialNumber.load();
+    int serial = serialNumber.loadRelaxed();
     if (!threadData->canWait || (serial != lastSerial)) {
         lastSerial = serial;
         QCoreApplication::sendPostedEvents();
diff --git a/src/plugins/platforms/cocoa/qnsview_drawing.mm b/src/plugins/platforms/cocoa/qnsview_drawing.mm
index e72142466b..ce5488ead0 100644
--- a/src/plugins/platforms/cocoa/qnsview_drawing.mm
+++ b/src/plugins/platforms/cocoa/qnsview_drawing.mm
@@ -43,9 +43,7 @@
 
 - (void)initDrawing
 {
-    self.wantsLayer = [self layerExplicitlyRequested]
-        || [self shouldUseMetalLayer]
-        || [self layerEnabledByMacOS];
+    [self updateLayerBacking];
 
     // Enable high-DPI OpenGL for retina displays. Enabling has the side
     // effect that Cocoa will start calling glViewport(0, 0, width, height),
@@ -71,22 +69,13 @@
     return YES;
 }
 
-- (void)drawRect:(NSRect)dirtyRect
-{
-    Q_UNUSED(dirtyRect);
-
-    if (!m_platformWindow)
-        return;
-
-    QRegion exposedRegion;
-    const NSRect *dirtyRects;
-    NSInteger numDirtyRects;
-    [self getRectsBeingDrawn:&dirtyRects count:&numDirtyRects];
-    for (int i = 0; i < numDirtyRects; ++i)
-        exposedRegion += QRectF::fromCGRect(dirtyRects[i]).toRect();
+// ----------------------- Layer setup -----------------------
 
-    qCDebug(lcQpaDrawing) << "[QNSView drawRect:]" << m_platformWindow->window() << exposedRegion;
-    m_platformWindow->handleExposeEvent(exposedRegion);
+- (void)updateLayerBacking
+{
+    self.wantsLayer = [self layerEnabledByMacOS]
+        || [self layerExplicitlyRequested]
+        || [self shouldUseMetalLayer];
 }
 
 - (BOOL)layerEnabledByMacOS
@@ -123,40 +112,81 @@
     return surfaceType == QWindow::MetalSurface || surfaceType == QWindow::VulkanSurface;
 }
 
+/*
+    This method is called by AppKit when layer-backing is requested by
+    setting wantsLayer too YES (via -[NSView _updateLayerBackedness]),
+    or in cases where AppKit itself decides that a view should be
+    layer-backed.
+
+    Note however that some code paths in AppKit will not go via this
+    method for creating the backing layer, and will instead create the
+    layer manually, and just call setLayer. An example of this is when
+    an NSOpenGLContext is attached to a view, in which case AppKit will
+    create a new layer in NSOpenGLContextSetLayerOnViewIfNecessary.
+
+    For this reason we leave the implementation of this override as
+    minimal as possible, only focusing on creating the appropriate
+    layer type, and then leave it up to setLayer to do the work of
+    making sure the layer is set up correctly.
+*/
 - (CALayer *)makeBackingLayer
 {
     if ([self shouldUseMetalLayer]) {
         // Check if Metal is supported. If it isn't then it's most likely
         // too late at this point and the QWindow will be non-functional,
         // but we can at least print a warning.
-        if (![MTLCreateSystemDefaultDevice() autorelease]) {
-            qWarning() << "QWindow initialization error: Metal is not supported";
-            return [super makeBackingLayer];
+        if ([MTLCreateSystemDefaultDevice() autorelease]) {
+            return [CAMetalLayer layer];
+        } else {
+            qCWarning(lcQpaDrawing) << "Failed to create QWindow::MetalSurface."
+                << "Metal is not supported by any of the GPUs in this system.";
         }
-
-        CAMetalLayer *layer = [CAMetalLayer layer];
-
-        // Set the contentsScale for the layer. This is normally done in
-        // viewDidChangeBackingProperties, however on startup that function
-        // is called before the layer is created here. The layer's drawableSize
-        // is updated from layoutSublayersOfLayer as usual.
-        layer.contentsScale = self.window.backingScaleFactor;
-
-        return layer;
     }
 
     return [super makeBackingLayer];
 }
 
+/*
+    This method is called by AppKit whenever the view is asked to change
+    its layer, which can happen both as a result of enabling layer-backing,
+    or when a layer is set explicitly. The latter can happen both when a
+    view is layer-hosting, or when AppKit internals are switching out the
+    layer-backed view, as described above for makeBackingLayer.
+*/
 - (void)setLayer:(CALayer *)layer
 {
-    qCDebug(lcQpaDrawing) << "Making" << self << "layer-backed with" << layer
-        << "due to being" << ([self layerExplicitlyRequested] ? "explicitly requested"
+    qCDebug(lcQpaDrawing) << "Making" << self
+        << (self.wantsLayer ? "layer-backed" : "layer-hosted")
+        << "with" << layer << "due to being" << ([self layerExplicitlyRequested] ? "explicitly requested"
             : [self shouldUseMetalLayer] ? "needed by surface type" : "enabled by macOS");
+
+    if (layer.delegate && layer.delegate != self) {
+        qCWarning(lcQpaDrawing) << "Layer already has delegate" << layer.delegate
+            << "This delegate is responsible for all view updates for" << self;
+    } else {
+        layer.delegate = self;
+    }
+
     [super setLayer:layer];
-    layer.delegate = self;
+
+    // When adding a view to a view hierarchy the backing properties will change
+    // which results in updating the contents scale, but in case of switching the
+    // layer on a view that's already in a view hierarchy we need to manually ensure
+    // the scale is up to date.
+    if (self.superview)
+        [self updateLayerContentsScale];
+
+    if (self.opaque && lcQpaDrawing().isDebugEnabled()) {
+        // If the view claims to be opaque we expect it to fill the entire
+        // layer with content, in which case we want to detect any areas
+        // where it doesn't.
+        layer.backgroundColor = NSColor.magentaColor.CGColor;
+    }
+
 }
 
+// ----------------------- Layer updates -----------------------
+
 - (NSViewLayerContentsRedrawPolicy)layerContentsRedrawPolicy
 {
     // We need to set this explicitly since the super implementation
@@ -164,17 +194,95 @@
     return NSViewLayerContentsRedrawDuringViewResize;
 }
 
-#if 0 // Disabled until we enable lazy backingstore resizing
 - (NSViewLayerContentsPlacement)layerContentsPlacement
 {
-    // Always place the layer at top left without any automatic scaling,
-    // so that we can re-use larger layers when resizing a window down.
+    // Always place the layer at top left without any automatic scaling.
+    // This will highlight situations where we're missing content for the
+    // layer by not responding to the displayLayer: request synchronously.
+    // It also allows us to re-use larger layers when resizing a window down.
     return NSViewLayerContentsPlacementTopLeft;
 }
-#endif
 
+- (void)viewDidChangeBackingProperties
+{
+    qCDebug(lcQpaDrawing) << "Backing properties changed for" << self;
+
+    if (self.layer)
+        [self updateLayerContentsScale];
+
+    // Ideally we would plumb this situation through QPA in a way that lets
+    // clients invalidate their own caches, recreate QBackingStore, etc.
+    // For now we trigger an expose, and let QCocoaBackingStore deal with
+    // buffer invalidation internally.
+    [self setNeedsDisplay:YES];
+}
+
+- (void)updateLayerContentsScale
+{
+    // We expect clients to fill the layer with retina aware content,
+    // based on the devicePixelRatio of the QWindow, so we set the
+    // layer's content scale to match that. By going via devicePixelRatio
+    // instead of applying the NSWindow's backingScaleFactor, we also take
+    // into account OpenGL views with wantsBestResolutionOpenGLSurface set
+    // to NO. In this case the window will have a backingScaleFactor of 2,
+    // but the QWindow will have a devicePixelRatio of 1.
+    auto devicePixelRatio = m_platformWindow->devicePixelRatio();
+    qCDebug(lcQpaDrawing) << "Updating" << self.layer << "content scale to" << devicePixelRatio;
+    self.layer.contentsScale = devicePixelRatio;
+}
+
+/*
+    This method is called by AppKit to determine whether it should update
+    the contentScale of the layer to match the window backing scale.
+
+    We always return NO since we're updating the contents scale manually.
+*/
+- (BOOL)layer:(CALayer *)layer shouldInheritContentsScale:(CGFloat)scale fromWindow:(NSWindow *)window
+{
+    Q_UNUSED(layer); Q_UNUSED(scale); Q_UNUSED(window);
+    return NO;
+}
+
+// ----------------------- Draw callbacks -----------------------
+
+/*
+    This method is called by AppKit for the non-layer case, where we are
+    drawing into the NSWindow's surface.
+*/
+- (void)drawRect:(NSRect)dirtyBoundingRect
+{
+    Q_ASSERT_X(!self.layer, "QNSView",
+        "The drawRect code path should not be hit when we are layer backed");
+
+    if (!m_platformWindow)
+        return;
+
+    QRegion exposedRegion;
+    const NSRect *dirtyRects;
+    NSInteger numDirtyRects;
+    [self getRectsBeingDrawn:&dirtyRects count:&numDirtyRects];
+    for (int i = 0; i < numDirtyRects; ++i)
+        exposedRegion += QRectF::fromCGRect(dirtyRects[i]).toRect();
+
+    if (exposedRegion.isEmpty())
+        exposedRegion = QRectF::fromCGRect(dirtyBoundingRect).toRect();
+
+    qCDebug(lcQpaDrawing) << "[QNSView drawRect:]" << m_platformWindow->window() << exposedRegion;
+    m_platformWindow->handleExposeEvent(exposedRegion);
+}
+
+/*
+    This method is called by AppKit when we are layer-backed, where
+    we are drawing into the layer.
+*/
 - (void)displayLayer:(CALayer *)layer
 {
+    Q_ASSERT_X(self.layer && layer == self.layer, "QNSView",
+        "The displayLayer code path should only be hit for our own layer");
+
+    if (!m_platformWindow)
+        return;
+
     if (!NSThread.isMainThread) {
         // Qt is calling AppKit APIs such as -[NSOpenGLContext setView:] on secondary threads,
         // which we shouldn't do. This may result in AppKit (wrongly) triggering a display on
@@ -184,29 +292,8 @@
         return;
     }
 
-    Q_ASSERT(layer == self.layer);
-
-    if (!m_platformWindow)
-        return;
-
     qCDebug(lcQpaDrawing) << "[QNSView displayLayer]" << m_platformWindow->window();
-
-    // FIXME: Find out if there's a way to resolve the dirty rect like in drawRect:
     m_platformWindow->handleExposeEvent(QRectF::fromCGRect(self.bounds).toRect());
 }
 
-- (void)viewDidChangeBackingProperties
-{
-    qCDebug(lcQpaDrawing) << "Backing properties changed for" << self;
-
-    if (self.layer)
-        self.layer.contentsScale = self.window.backingScaleFactor;
-
-    // Ideally we would plumb this situation through QPA in a way that lets
-    // clients invalidate their own caches, recreate QBackingStore, etc.
-    // For now we trigger an expose, and let QCocoaBackingStore deal with
-    // buffer invalidation internally.
-    [self setNeedsDisplay:YES];
-}
-
 @end
diff --git a/src/plugins/platforms/windows/qwindowsglcontext.cpp b/src/plugins/platforms/windows/qwindowsglcontext.cpp
index 3591b2c505..d9521e7e08 100644
--- a/src/plugins/platforms/windows/qwindowsglcontext.cpp
+++ b/src/plugins/platforms/windows/qwindowsglcontext.cpp
@@ -891,13 +891,6 @@ QWindowsOpenGLContextFormat QWindowsOpenGLContextFormat::current()
         result.profile = QSurfaceFormat::CoreProfile;
     else if (value & GL_CONTEXT_COMPATIBILITY_PROFILE_BIT)
         result.profile = QSurfaceFormat::CompatibilityProfile;
-    if (result.version < 0x0400)
-        return result;
-    // v4.0 onwards
-    value = 0;
-    QOpenGLStaticContext::opengl32.glGetIntegerv(RESET_NOTIFICATION_STRATEGY_ARB, &value);
-    if (value == LOSE_CONTEXT_ON_RESET_ARB)
-        result.options |= QSurfaceFormat::ResetNotification;
     return result;
 }
 
@@ -975,6 +968,7 @@ QOpenGLTemporaryContext::~QOpenGLTemporaryContext()
 */
 
 #define SAMPLE_BUFFER_EXTENSION "GL_ARB_multisample"
+#define ROBUSTNESS_EXTENSION "GL_ARB_robustness"
 
 QOpenGLStaticContext::QOpenGLStaticContext() :
     vendor(QOpenGLStaticContext::getGlString(GL_VENDOR)),
@@ -995,9 +989,31 @@ QOpenGLStaticContext::QOpenGLStaticContext() :
     wglGetExtensionsStringARB(reinterpret_cast<WglGetExtensionsStringARB>(
         reinterpret_cast<QFunctionPointer>(QOpenGLStaticContext::opengl32.wglGetProcAddress("wglGetExtensionsStringARB"))))
 {
-    if (extensionNames.startsWith(SAMPLE_BUFFER_EXTENSION " ")
-            || extensionNames.indexOf(" " SAMPLE_BUFFER_EXTENSION " ") != -1)
-        extensions |= SampleBuffers;
+    if (defaultFormat.version < 0x0300) {
+        if (extensionNames.startsWith(SAMPLE_BUFFER_EXTENSION " ")
+                || extensionNames.indexOf(" " SAMPLE_BUFFER_EXTENSION " ") != -1)
+            extensions |= SampleBuffers;
+        if (extensionNames.startsWith(ROBUSTNESS_EXTENSION " ")
+                || extensionNames.indexOf(" " ROBUSTNESS_EXTENSION " ") != -1)
+            extensions |= Robustness;
+    } else {
+        typedef const GLubyte * (APIENTRY *glGetStringi_t)(GLenum, GLuint);
+        auto glGetStringi = reinterpret_cast<glGetStringi_t>(
+            reinterpret_cast<QFunctionPointer>(QOpenGLStaticContext::opengl32.wglGetProcAddress("glGetStringi")));
+        if (glGetStringi) {
+            GLint n = 0;
+            QOpenGLStaticContext::opengl32.glGetIntegerv(GL_NUM_EXTENSIONS, &n);
+            for (GLint i = 0; i < n; ++i) {
+                const char *p = reinterpret_cast<const char *>(glGetStringi(GL_EXTENSIONS, i));
+                if (p) {
+                    if (!strcmp(p, SAMPLE_BUFFER_EXTENSION))
+                        extensions |= SampleBuffers;
+                    else if (!strcmp(p, ROBUSTNESS_EXTENSION))
+                        extensions |= Robustness;
+                }
+            }
+        }
+    }
 }
 
 QByteArray QOpenGLStaticContext::getGlString(unsigned int which)
@@ -1236,27 +1252,11 @@ bool QWindowsGLContext::updateObtainedParams(HDC hdc, int *obtainedSwapInterval)
     if (m_staticContext->wglGetSwapInternalExt && obtainedSwapInterval)
         *obtainedSwapInterval = m_staticContext->wglGetSwapInternalExt();
 
-    bool hasRobustness = false;
-    if (m_obtainedFormat.majorVersion() < 3) {
-        const char *exts = reinterpret_cast<const char *>(QOpenGLStaticContext::opengl32.glGetString(GL_EXTENSIONS));
-        hasRobustness = exts && strstr(exts, "GL_ARB_robustness");
-    } else {
-        typedef const GLubyte * (APIENTRY *glGetStringi_t)(GLenum, GLuint);
-        auto glGetStringi = reinterpret_cast<glGetStringi_t>(
-            reinterpret_cast<QFunctionPointer>(QOpenGLStaticContext::opengl32.wglGetProcAddress("glGetStringi")));
-        if (glGetStringi) {
-            GLint n = 0;
-            QOpenGLStaticContext::opengl32.glGetIntegerv(GL_NUM_EXTENSIONS, &n);
-            for (GLint i = 0; i < n; ++i) {
-                const char *p = reinterpret_cast<const char *>(glGetStringi(GL_EXTENSIONS, i));
-                if (p && !strcmp(p, "GL_ARB_robustness")) {
-                    hasRobustness = true;
-                    break;
-                }
-            }
-        }
-    }
-    if (hasRobustness) {
+    if (testFlag(m_staticContext->extensions, QOpenGLStaticContext::Robustness)) {
+        GLint value = 0;
+        QOpenGLStaticContext::opengl32.glGetIntegerv(RESET_NOTIFICATION_STRATEGY_ARB, &value);
+        if (value == LOSE_CONTEXT_ON_RESET_ARB)
+            m_obtainedFormat.setOption(QSurfaceFormat::ResetNotification);
         m_getGraphicsResetStatus = reinterpret_cast<GlGetGraphicsResetStatusArbType>(
             reinterpret_cast<QFunctionPointer>(QOpenGLStaticContext::opengl32.wglGetProcAddress("glGetGraphicsResetStatusARB")));
     }
diff --git a/src/plugins/platforms/windows/qwindowsglcontext.h b/src/plugins/platforms/windows/qwindowsglcontext.h
index e962af39c2..e5f6fefd5a 100644
--- a/src/plugins/platforms/windows/qwindowsglcontext.h
+++ b/src/plugins/platforms/windows/qwindowsglcontext.h
@@ -142,7 +142,8 @@ public:
     enum Extensions
     {
         SampleBuffers = 0x1,
-        sRGBCapableFramebuffer = 0x2
+        sRGBCapableFramebuffer = 0x2,
+        Robustness = 0x4,
     };
 
     typedef bool
diff --git a/src/plugins/platforms/windows/qwindowsopengltester.cpp b/src/plugins/platforms/windows/qwindowsopengltester.cpp
index 63ecbfe0ea..afc1991e2c 100644
--- a/src/plugins/platforms/windows/qwindowsopengltester.cpp
+++ b/src/plugins/platforms/windows/qwindowsopengltester.cpp
@@ -47,7 +47,6 @@
 #include <QtCore/qfile.h>
 #include <QtCore/qfileinfo.h>
 #include <QtCore/qstandardpaths.h>
-#include <QtCore/qlibrary.h>
 #include <QtCore/qlibraryinfo.h>
 #include <QtCore/qhash.h>
 
@@ -58,8 +57,6 @@
 #include <QtCore/qt_windows.h>
 #include <private/qsystemlibrary_p.h>
 #include <d3d9.h>
-#include <d3d10.h>
-#include <dxgi.h>
 
 QT_BEGIN_NAMESPACE
 
@@ -83,259 +80,52 @@ static GpuDescription adapterIdentifierToGpuDescription(const D3DADAPTER_IDENTIF
     return result;
 }
 
-class QGraphicsAdapterInfo
+class QDirect3D9Handle
 {
 public:
-    Q_DISABLE_COPY_MOVE(QGraphicsAdapterInfo)
+    Q_DISABLE_COPY_MOVE(QDirect3D9Handle)
 
-    QGraphicsAdapterInfo();
-    ~QGraphicsAdapterInfo();
+    QDirect3D9Handle();
+    ~QDirect3D9Handle();
 
-    bool isValid() const;
+    bool isValid() const { return m_direct3D9 != nullptr; }
 
-    UINT adapterCount() const;
+    UINT adapterCount() const { return m_direct3D9 ? m_direct3D9->GetAdapterCount() : 0u; }
     bool retrieveAdapterIdentifier(UINT n, D3DADAPTER_IDENTIFIER9 *adapterIdentifier) const;
 
 private:
-    QSystemLibrary m_dxgilib;
-    IDXGIFactory1 *m_dxgiFactory1 = nullptr;
-
     QSystemLibrary m_d3d9lib;
     IDirect3D9 *m_direct3D9 = nullptr;
-
-    /* This is a value from the DXGI_ADAPTER_FLAG enum.
-     * However, it's not available in dxgi.h from MinGW,
-     * so define it here in any case. */
-    enum { DXGI_ADAPTER_FLAG_SOFTWARE = 2 };
-
-    UINT adapterCountDXGI() const;
-    bool retrieveAdapterIdentifierDXGI(UINT n, D3DADAPTER_IDENTIFIER9 *adapterIdentifier) const;
-
-    UINT adapterCountD3D9() const;
-    bool retrieveAdapterIdentifierD3D9(UINT n, D3DADAPTER_IDENTIFIER9 *adapterIdentifier) const;
 };
 
-QGraphicsAdapterInfo::QGraphicsAdapterInfo() :
-    m_dxgilib(QStringLiteral("dxgi")),
+QDirect3D9Handle::QDirect3D9Handle() :
     m_d3d9lib(QStringLiteral("d3d9"))
 {
-    using PtrCreateDXGIFactory1 = HRESULT (WINAPI *)(REFIID, void**);
+    using PtrDirect3DCreate9 = IDirect3D9 *(WINAPI *)(UINT);
 
-    if (m_dxgilib.load()) {
-        if (auto createDXGIFactory1 = (PtrCreateDXGIFactory1)m_dxgilib.resolve("CreateDXGIFactory1"))
-            createDXGIFactory1(IID_PPV_ARGS(&m_dxgiFactory1));
-    }
-
-    if (!m_dxgiFactory1) {
-        using PtrDirect3DCreate9 = IDirect3D9 *(WINAPI *)(UINT);
-
-        if (m_d3d9lib.load()) {
-            if (auto direct3DCreate9 = (PtrDirect3DCreate9)m_d3d9lib.resolve("Direct3DCreate9"))
-                m_direct3D9 = direct3DCreate9(D3D_SDK_VERSION);
-        }
+    if (m_d3d9lib.load()) {
+        if (auto direct3DCreate9 = (PtrDirect3DCreate9)m_d3d9lib.resolve("Direct3DCreate9"))
+            m_direct3D9 = direct3DCreate9(D3D_SDK_VERSION);
     }
 }
 
-QGraphicsAdapterInfo::~QGraphicsAdapterInfo()
+QDirect3D9Handle::~QDirect3D9Handle()
 {
-    if (m_dxgiFactory1)
-       m_dxgiFactory1->Release();
     if (m_direct3D9)
        m_direct3D9->Release();
 }
 
-bool QGraphicsAdapterInfo::isValid() const
-{
-    return m_dxgiFactory1 != nullptr || m_direct3D9 != nullptr;
-}
-
-UINT QGraphicsAdapterInfo::adapterCount() const
-{
-    if (m_dxgiFactory1)
-        return adapterCountDXGI();
-    if (m_direct3D9)
-        return adapterCountD3D9();
-    return 0;
-}
-
-bool QGraphicsAdapterInfo::retrieveAdapterIdentifier(UINT n, D3DADAPTER_IDENTIFIER9 *adapterIdentifier) const
-{
-    if (m_dxgiFactory1)
-        return retrieveAdapterIdentifierDXGI(n, adapterIdentifier);
-    if (m_direct3D9)
-        return retrieveAdapterIdentifierD3D9(n, adapterIdentifier);
-    return false;
-}
-
-UINT QGraphicsAdapterInfo::adapterCountDXGI() const
-{
-    /* DXGI doesn't have an adapterCount(), instead we have to call EnumAdapters1()
-     * until DXGI_ERROR_NOT_FOUND is returned. */
-    UINT n = 0;
-
-    IDXGIAdapter1 *adapter;
-    while (SUCCEEDED(m_dxgiFactory1->EnumAdapters1(n, &adapter))) {
-        adapter->Release();
-        ++n;
-    }
-
-    return n;
-}
-
-// Detect whether we are running under 64-bit Windows.
-static bool isWow64Process()
-{
-    typedef BOOL (WINAPI *IsWow64ProcessPtr)(HANDLE hProcess, PBOOL Wow64Process);
-    IsWow64ProcessPtr IsWow64Process = (IsWow64ProcessPtr)QLibrary::resolve(
-                QStringLiteral("kernel32.dll"), "IsWow64Process");
-
-    if (IsWow64Process) {
-        BOOL IsWow64 = FALSE;
-        if (IsWow64Process(GetCurrentProcess(), &IsWow64))
-            return IsWow64;
-    }
-    return false;
-}
-
-// Read a string value from registry
-static QString regGetString(HKEY key, const wchar_t* valueName)
-{
-    QVarLengthArray<wchar_t, MAX_PATH> buf (MAX_PATH);
-    LRESULT res;
-    DWORD bufSize = buf.size() * sizeof(wchar_t);
-    res = RegGetValue(key, nullptr, valueName,
-                      RRF_RT_REG_SZ | RRF_RT_REG_MULTI_SZ, nullptr,
-                      buf.data(), &bufSize);
-    if (res == ERROR_MORE_DATA) {
-        buf.resize(bufSize / sizeof(wchar_t));
-        bufSize = buf.size() * sizeof(wchar_t);
-        res = RegGetValue(key, nullptr, valueName,
-                        RRF_RT_REG_SZ | RRF_RT_REG_MULTI_SZ, nullptr,
-                        buf.data(), &bufSize);
-    }
-    /* In case of REG_MULTI_SZ, this returns just the first string,
-     * but that is sufficient for our purposes. */
-    if (res == ERROR_SUCCESS)
-        return QString::fromWCharArray(buf.data());
-    return QString();
-}
-
-// Read driver name given a DeviceKey
-static QString retrieveDriverName(const wchar_t *driverKey)
-{
-    /* Kernel-style prefix, maps to HKLM
-     * (see https://docs.microsoft.com/en-us/windows-hardware/drivers/kernel/registry-key-object-routines) */
-    static const wchar_t prefixMappingHKLM[] = L"\\Registry\\Machine\\";
-    const size_t prefixMappingHKLMLen = wcslen(prefixMappingHKLM);
-    if (wcsnicmp(driverKey, prefixMappingHKLM, prefixMappingHKLMLen) != 0)
-        return QString();
-
-    driverKey += prefixMappingHKLMLen;
-    QString driverPath;
-    HKEY key;
-    if (RegOpenKeyEx(HKEY_LOCAL_MACHINE, driverKey, 0, KEY_READ | KEY_WOW64_64KEY, &key) == ERROR_SUCCESS) {
-        const wchar_t *valueName =
-                isWow64Process() ? L"UserModeDriverNameWow" : L"UserModeDriverName";
-        driverPath = regGetString(key, valueName);
-        RegCloseKey(key);
-    }
-    if (!driverPath.isEmpty()) {
-        int fileNameSep = driverPath.lastIndexOf(QLatin1Char('\\'));
-        if (fileNameSep >= 0)
-            driverPath = driverPath.mid(fileNameSep + 1);
-        return driverPath;
-    }
-    return QString();
-}
-
-// Retrieve driver name for a display device from registry.
-static QString driverNameForDevice(const wchar_t *displayDevice)
-{
-    QString driverName;
-    DISPLAY_DEVICE dd;
-    memset(&dd, 0, sizeof(dd));
-    dd.cb = sizeof(dd);
-    for (int dev = 0; EnumDisplayDevices(nullptr, dev, &dd, 0); ++dev) {
-        if (wcsicmp(displayDevice, dd.DeviceName) == 0) {
-            // DeviceKey is documented as "internal", but it's a registry key in kernel format
-            driverName = retrieveDriverName(dd.DeviceKey);
-            break;
-        }
-    }
-    if (driverName.isEmpty()) {
-        /* Fall back to driver name from EnumDisplaySettings.
-         * This is only a fallback as on Windows 10 this just returns an device-independent
-         * name. OTOH, it's possible to recognize RDP connections from the driver name. */
-        DEVMODE devMode;
-        if (EnumDisplaySettings(displayDevice, ENUM_CURRENT_SETTINGS, &devMode))
-            driverName = QString::fromWCharArray(devMode.dmDeviceName);
-    }
-    return driverName;
-}
-
-bool QGraphicsAdapterInfo::retrieveAdapterIdentifierDXGI(UINT n, D3DADAPTER_IDENTIFIER9 *adapterIdentifier) const
-{
-    IDXGIAdapter1 *adapter;
-    if (FAILED(m_dxgiFactory1->EnumAdapters1(n, &adapter)))
-        return false;
-
-    bool result = false;
-
-    DXGI_ADAPTER_DESC1 adapterDesc;
-    if (SUCCEEDED(adapter->GetDesc1(&adapterDesc))) {
-        if ((adapterDesc.VendorId != 0) && (adapterDesc.DeviceId != 0) // Don't use adapter description of Software Devices
-            && ((adapterDesc.Flags & DXGI_ADAPTER_FLAG_SOFTWARE) == 0)) {
-            memset(adapterIdentifier, 0, sizeof(*adapterIdentifier));
-            WideCharToMultiByte(1252, 0, adapterDesc.Description, -1,
-                                adapterIdentifier->Description,
-                                sizeof(adapterIdentifier->Description), nullptr, nullptr);
-            adapterIdentifier->Description[sizeof(adapterIdentifier->Description) - 1] = 0;
-            adapterIdentifier->VendorId = adapterDesc.VendorId;
-            adapterIdentifier->DeviceId = adapterDesc.DeviceId;
-            adapterIdentifier->SubSysId = adapterDesc.SubSysId;
-            adapterIdentifier->Revision = adapterDesc.Revision;
-
-            LARGE_INTEGER umdVersion;
-            if (SUCCEEDED(adapter->CheckInterfaceSupport(__uuidof(ID3D10Device), &umdVersion))) {
-                adapterIdentifier->DriverVersion = umdVersion;
-                result = true;
-            }
-
-            /* DXGI doesn't expose the driver name, but we can get it from the registry.
-             * But we need a device name to follow. */
-            IDXGIOutput *output = nullptr;
-            if (SUCCEEDED(adapter->EnumOutputs (0, &output))) {
-                DXGI_OUTPUT_DESC outputDesc;
-                if (SUCCEEDED(output->GetDesc (&outputDesc))) {
-                    QString driverName = driverNameForDevice(outputDesc.DeviceName);
-                    qstrncpy(adapterIdentifier->Driver, driverName.toLatin1().constData(),
-                             sizeof(adapterIdentifier->Driver));
-                }
-                output->Release();
-            }
-        }
-    }
-
-    adapter->Release();
-
-    return result;
-}
-
-UINT QGraphicsAdapterInfo::adapterCountD3D9() const
-{
-    return m_direct3D9->GetAdapterCount();
-}
-
-bool QGraphicsAdapterInfo::retrieveAdapterIdentifierD3D9(UINT n, D3DADAPTER_IDENTIFIER9 *adapterIdentifier) const
+bool QDirect3D9Handle::retrieveAdapterIdentifier(UINT n, D3DADAPTER_IDENTIFIER9 *adapterIdentifier) const
 {
-    return SUCCEEDED(m_direct3D9->GetAdapterIdentifier(n, 0, adapterIdentifier));
+    return m_direct3D9
+        && SUCCEEDED(m_direct3D9->GetAdapterIdentifier(n, 0, adapterIdentifier));
 }
 
 GpuDescription GpuDescription::detect()
 {
     GpuDescription result;
-    QGraphicsAdapterInfo adapterInfo;
-    if (!adapterInfo.isValid())
+    QDirect3D9Handle direct3D9;
+    if (!direct3D9.isValid())
         return result;
 
     D3DADAPTER_IDENTIFIER9 adapterIdentifier;
@@ -346,7 +136,7 @@ GpuDescription GpuDescription::detect()
     // and D3D uses by default. Therefore querying any additional adapters is
     // futile and not useful for our purposes in general, except for
     // identifying a few special cases later on.
-    if (adapterInfo.retrieveAdapterIdentifier(0, &adapterIdentifier)) {
+    if (direct3D9.retrieveAdapterIdentifier(0, &adapterIdentifier)) {
         result = adapterIdentifierToGpuDescription(adapterIdentifier);
         isAMD = result.vendorId == VENDOR_ID_AMD;
     }
@@ -355,9 +145,9 @@ GpuDescription GpuDescription::detect()
     // when starting apps on a screen connected to the Intel card) by looking
     // for a default AMD adapter and an additional non-AMD one.
     if (isAMD) {
-        const UINT adapterCount = adapterInfo.adapterCount();
+        const UINT adapterCount = direct3D9.adapterCount();
         for (UINT adp = 1; adp < adapterCount; ++adp) {
-            if (adapterInfo.retrieveAdapterIdentifier(adp, &adapterIdentifier)
+            if (direct3D9.retrieveAdapterIdentifier(adp, &adapterIdentifier)
                 && adapterIdentifier.VendorId != VENDOR_ID_AMD) {
                 // Bingo. Now figure out the display for the AMD card.
                 DISPLAY_DEVICE dd;
@@ -382,11 +172,11 @@ GpuDescription GpuDescription::detect()
 QVector<GpuDescription> GpuDescription::detectAll()
 {
     QVector<GpuDescription> result;
-    QGraphicsAdapterInfo adapterInfo;
-    if (const UINT adapterCount = adapterInfo.adapterCount()) {
+    QDirect3D9Handle direct3D9;
+    if (const UINT adapterCount = direct3D9.adapterCount()) {
         for (UINT adp = 0; adp < adapterCount; ++adp) {
             D3DADAPTER_IDENTIFIER9 adapterIdentifier;
-            if (adapterInfo.retrieveAdapterIdentifier(adp, &adapterIdentifier))
+            if (direct3D9.retrieveAdapterIdentifier(adp, &adapterIdentifier))
                 result.append(adapterIdentifierToGpuDescription(adapterIdentifier));
         }
     }
diff --git a/src/plugins/platforms/windows/qwindowswindow.cpp b/src/plugins/platforms/windows/qwindowswindow.cpp
index 1196190b81..5c13bd9650 100644
--- a/src/plugins/platforms/windows/qwindowswindow.cpp
+++ b/src/plugins/platforms/windows/qwindowswindow.cpp
@@ -2697,10 +2697,16 @@ bool QWindowsWindow::handleNonClientHitTest(const QPoint &globalPos, LRESULT *re
             return true;
         }
         if (localPos.y() < 0) {
-            const int topResizeBarPos = -frameMargins().top();
-            if (localPos.y() >= topResizeBarPos)
+            // We want to return HTCAPTION/true only over the outer sizing frame, not the entire title bar,
+            // otherwise the title bar buttons (close, etc.) become unresponsive on Windows 7 (QTBUG-78262).
+            // However, neither frameMargins() nor GetSystemMetrics(SM_CYSIZEFRAME), etc., give the correct
+            // sizing frame height in all Windows versions/scales. This empirical constant seems to work, though.
+            const int sizingHeight = 9;
+            const int topResizeBarPos = sizingHeight - frameMargins().top();
+            if (localPos.y() < topResizeBarPos) {
                 *result = HTCAPTION; // Extend caption over top resize bar, let's user move the window.
-            return true;
+                return true;
+            }
         }
     }
     if (fixedWidth && (localPos.x() < 0 || localPos.x() >= size.width())) {
diff --git a/src/plugins/platforms/windows/windows.pri b/src/plugins/platforms/windows/windows.pri
index 7de6369541..95ba961df1 100644
--- a/src/plugins/platforms/windows/windows.pri
+++ b/src/plugins/platforms/windows/windows.pri
@@ -12,8 +12,6 @@ LIBS += -lshlwapi -lwtsapi32
 QMAKE_USE_PRIVATE += \
     advapi32 \
     d3d9/nolink \
-    d3d11/nolink \
-    dxgi/nolink \
     ole32 \
     shell32 \
     user32 \