10 files changed, 42 insertions, 5 deletions
diff --git a/src/gui/painting/qplatformbackingstore.cpp b/src/gui/painting/qplatformbackingstore.cpp
index 601dc97be1..45e90bd99b 100644
--- a/src/gui/painting/qplatformbackingstore.cpp
+++ b/src/gui/painting/qplatformbackingstore.cpp
@@ -338,7 +338,16 @@ void QPlatformBackingStore::composeAndFlush(QWindow *window, const QRegion &regi
         }
     }
 
-    if (!d_ptr->context->makeCurrent(window)) {
+    bool current = d_ptr->context->makeCurrent(window);
+
+    if (!current && !d_ptr->context->isValid()) {
+        delete d_ptr->blitter;
+        d_ptr->blitter = nullptr;
+        d_ptr->textureId = 0;
+        current = d_ptr->context->create() && d_ptr->context->makeCurrent(window);
+    }
+
+    if (!current) {
         qCWarning(lcQpaBackingStore, "composeAndFlush: makeCurrent() failed");
         return;
     }
diff --git a/src/gui/rhi/qrhivulkan.cpp b/src/gui/rhi/qrhivulkan.cpp
index 36a6557e04..d07777d63a 100644
--- a/src/gui/rhi/qrhivulkan.cpp
+++ b/src/gui/rhi/qrhivulkan.cpp
@@ -1705,6 +1705,10 @@ QRhi::FrameOpResult QRhiVulkan::endFrame(QRhiSwapChain *swapChain, QRhi::EndFram
         presInfo.waitSemaphoreCount = 1;
         presInfo.pWaitSemaphores = &frame.drawSem; // gfxQueueFamilyIdx == presQueueFamilyIdx ? &frame.drawSem : &frame.presTransSem;
 
+        // Do platform-specific WM notification. F.ex. essential on Wayland in
+        // order to circumvent driver frame callbacks
+        inst->presentAboutToBeQueued(swapChainD->window);
+
         VkResult err = vkQueuePresentKHR(gfxQueue, &presInfo);
         if (err != VK_SUCCESS) {
             if (err == VK_ERROR_OUT_OF_DATE_KHR) {
diff --git a/src/gui/text/qfont.cpp b/src/gui/text/qfont.cpp
index efc79a1783..76fde5388c 100644
--- a/src/gui/text/qfont.cpp
+++ b/src/gui/text/qfont.cpp
@@ -3176,8 +3176,7 @@ QDebug operator<<(QDebug stream, const QFont &font)
     QDebug debug(&fontDescription);
     debug.nospace();
 
-    QFontPrivate priv;
-    const QFont defaultFont(&priv);
+    const QFont defaultFont(new QFontPrivate);
 
     for (int property = QFont::FamilyResolved; property < QFont::AllPropertiesResolved; property <<= 1) {
         const bool resolved = (font.resolve_mask & property) != 0;
diff --git a/src/gui/text/qfontdatabase.cpp b/src/gui/text/qfontdatabase.cpp
index ce6bb0c347..261e1d831b 100644
--- a/src/gui/text/qfontdatabase.cpp
+++ b/src/gui/text/qfontdatabase.cpp
@@ -2684,7 +2684,7 @@ QFontEngine *QFontDatabase::findFont(const QFontDef &request, int script)
     QtFontDesc desc;
     QList<int> blackListed;
     int index = match(multi ? QChar::Script_Common : script, request, family_name, foundry_name, &desc, blackListed);
-    if (index < 0 && QGuiApplicationPrivate::platformIntegration()->fontDatabase()->populateFamilyAliases()) {
+    if (index < 0 && QGuiApplicationPrivate::platformIntegration()->fontDatabase()->populateFamilyAliases(family_name)) {
         // We populated familiy aliases (e.g. localized families), so try again
         index = match(multi ? QChar::Script_Common : script, request, family_name, foundry_name, &desc, blackListed);
     }
diff --git a/src/gui/text/qplatformfontdatabase.h b/src/gui/text/qplatformfontdatabase.h
index 38ba7f10b2..f79c5db625 100644
--- a/src/gui/text/qplatformfontdatabase.h
+++ b/src/gui/text/qplatformfontdatabase.h
@@ -104,7 +104,7 @@ class Q_GUI_EXPORT QPlatformFontDatabase
 public:
     virtual ~QPlatformFontDatabase();
     virtual void populateFontDatabase();
-    virtual bool populateFamilyAliases() { return false; }
+    virtual bool populateFamilyAliases(const QString &missingFamily) { Q_UNUSED(missingFamily); return false; }
     virtual void populateFamily(const QString &familyName);
     virtual void invalidate();
 
diff --git a/src/gui/vulkan/qplatformvulkaninstance.cpp b/src/gui/vulkan/qplatformvulkaninstance.cpp
index 9d044bfd58..1b5d3370f0 100644
--- a/src/gui/vulkan/qplatformvulkaninstance.cpp
+++ b/src/gui/vulkan/qplatformvulkaninstance.cpp
@@ -80,6 +80,11 @@ QPlatformVulkanInstance::~QPlatformVulkanInstance()
 {
 }
 
+void QPlatformVulkanInstance::presentAboutToBeQueued(QWindow *window)
+{
+    Q_UNUSED(window);
+}
+
 void QPlatformVulkanInstance::presentQueued(QWindow *window)
 {
     Q_UNUSED(window);
diff --git a/src/gui/vulkan/qplatformvulkaninstance.h b/src/gui/vulkan/qplatformvulkaninstance.h
index d47c59b5db..f96f1720fb 100644
--- a/src/gui/vulkan/qplatformvulkaninstance.h
+++ b/src/gui/vulkan/qplatformvulkaninstance.h
@@ -77,6 +77,7 @@ public:
     virtual QByteArrayList enabledExtensions() const = 0;
     virtual PFN_vkVoidFunction getInstanceProcAddr(const char *name) = 0;
     virtual bool supportsPresent(VkPhysicalDevice physicalDevice, uint32_t queueFamilyIndex, QWindow *window) = 0;
+    virtual void presentAboutToBeQueued(QWindow *window);
     virtual void presentQueued(QWindow *window);
     virtual void setDebugFilters(const QVector<QVulkanInstance::DebugFilter> &filters);
 
diff --git a/src/gui/vulkan/qvulkaninstance.cpp b/src/gui/vulkan/qvulkaninstance.cpp
index 0605d88cca..daf37e3dc8 100644
--- a/src/gui/vulkan/qvulkaninstance.cpp
+++ b/src/gui/vulkan/qvulkaninstance.cpp
@@ -775,6 +775,20 @@ bool QVulkanInstance::supportsPresent(VkPhysicalDevice physicalDevice, uint32_t
 }
 
 /*!
+    This function should be called by the application's renderer before queuing
+    a present operation for \a window.
+
+    While on some platforms this will be a no-op, some may perform windowing
+    system dependent synchronization. For example, on Wayland this will
+    add send a wl_surface.frame request in order to prevent the driver from
+    blocking for minimized windows.
+ */
+void QVulkanInstance::presentAboutToBeQueued(QWindow *window)
+{
+    d_ptr->platformInst->presentAboutToBeQueued(window);
+}
+
+/*!
     This function should be called by the application's renderer after queuing
     a present operation for \a window.
 
diff --git a/src/gui/vulkan/qvulkaninstance.h b/src/gui/vulkan/qvulkaninstance.h
index 70f2fd5102..5b3db9a4c8 100644
--- a/src/gui/vulkan/qvulkaninstance.h
+++ b/src/gui/vulkan/qvulkaninstance.h
@@ -186,6 +186,7 @@ public:
 
     bool supportsPresent(VkPhysicalDevice physicalDevice, uint32_t queueFamilyIndex, QWindow *window);
 
+    void presentAboutToBeQueued(QWindow *window);
     void presentQueued(QWindow *window);
 
     typedef bool (*DebugFilter)(VkDebugReportFlagsEXT flags, VkDebugReportObjectTypeEXT objectType, uint64_t object,
diff --git a/src/gui/vulkan/qvulkanwindow.cpp b/src/gui/vulkan/qvulkanwindow.cpp
index caf53eb586..790bef9e14 100644
--- a/src/gui/vulkan/qvulkanwindow.cpp
+++ b/src/gui/vulkan/qvulkanwindow.cpp
@@ -2018,6 +2018,10 @@ void QVulkanWindowPrivate::endFrame()
     presInfo.waitSemaphoreCount = 1;
     presInfo.pWaitSemaphores = gfxQueueFamilyIdx == presQueueFamilyIdx ? &frame.drawSem : &frame.presTransSem;
 
+    // Do platform-specific WM notification. F.ex. essential on Wayland in
+    // order to circumvent driver frame callbacks
+    inst->presentAboutToBeQueued(q);
+
     err = vkQueuePresentKHR(gfxQueue, &presInfo);
     if (err != VK_SUCCESS) {
         if (err == VK_ERROR_OUT_OF_DATE_KHR) {