plugins/qpa: support recovering from GPU resets

When the context experienced a GPU reset, the context and all swapchains need
to be recreated or there will be glitches

src/plugins/qpa/backingstore.cpp

@@ -42,7 +42,7 @@ void BackingStore::resize(const QSize &size, const QRegion &staticContents)
 void BackingStore::beginPaint(const QRegion &region)
 {
     Window *platformWindow = static_cast<Window *>(window()->handle());
-    Swapchain *swapchain = platformWindow->swapchain({{DRM_FORMAT_ARGB8888, {DRM_FORMAT_MOD_LINEAR}}});
+    Swapchain *swapchain = platformWindow->swapchain(nullptr, {{DRM_FORMAT_ARGB8888, {DRM_FORMAT_MOD_LINEAR}}});
     if (!swapchain) {
         qCCritical(KWIN_QPA, "Failed to ceate a swapchain for the backing store!");
         return;

src/plugins/qpa/eglplatformcontext.cpp

@@ -51,6 +51,9 @@ EGLPlatformContext::EGLPlatformContext(QOpenGLContext *context, EglDisplay *disp
 
 EGLPlatformContext::~EGLPlatformContext()
 {
+    if (!m_eglContext) {
+        return;
+    }
     if (!m_renderTargets.empty() || !m_zombieRenderTargets.empty()) {
         m_eglContext->makeCurrent();
         m_renderTargets.clear();
@@ -60,11 +63,20 @@ EGLPlatformContext::~EGLPlatformContext()
 
 bool EGLPlatformContext::makeCurrent(QPlatformSurface *surface)
 {
+    if (!m_eglContext) {
+        return false;
+    }
     const bool ok = m_eglContext->makeCurrent();
     if (!ok) {
         qCWarning(KWIN_QPA, "eglMakeCurrent failed: %x", eglGetError());
         return false;
     }
+    if (m_eglContext->checkGraphicsResetStatus() != GL_NO_ERROR) {
+        m_renderTargets.clear();
+        m_zombieRenderTargets.clear();
+        m_eglContext.reset();
+        return false;
+    }
 
     m_zombieRenderTargets.clear();
 
@@ -75,7 +87,7 @@ bool EGLPlatformContext::makeCurrent(QPlatformSurface *surface)
         QOpenGLContextPrivate::setCurrentContext(context());
 
         Window *window = static_cast<Window *>(surface);
-        Swapchain *swapchain = window->swapchain(m_eglDisplay->nonExternalOnlySupportedDrmFormats());
+        Swapchain *swapchain = window->swapchain(m_eglContext, m_eglDisplay->nonExternalOnlySupportedDrmFormats());
 
         GraphicsBuffer *buffer = swapchain->acquire();
         if (!buffer) {
@@ -116,7 +128,9 @@ bool EGLPlatformContext::makeCurrent(QPlatformSurface *surface)
 
 void EGLPlatformContext::doneCurrent()
 {
-    m_eglContext->doneCurrent();
+    if (m_eglContext) {
+        m_eglContext->doneCurrent();
+    }
 }
 
 bool EGLPlatformContext::isValid() const

src/plugins/qpa/eglplatformcontext.h

@@ -65,7 +65,7 @@ private:
     EglDisplay *m_eglDisplay = nullptr;
     QSurfaceFormat m_format;
     EGLConfig m_config = EGL_NO_CONFIG_KHR;
-    std::unique_ptr<EglContext> m_eglContext;
+    std::shared_ptr<EglContext> m_eglContext;
     std::unordered_map<GraphicsBuffer *, std::shared_ptr<EGLRenderTarget>> m_renderTargets;
     std::vector<std::shared_ptr<EGLRenderTarget>> m_zombieRenderTargets;
     std::shared_ptr<EGLRenderTarget> m_current;

src/plugins/qpa/window.cpp

@@ -43,13 +43,14 @@ Window::~Window()
     unmap();
 }
 
-Swapchain *Window::swapchain(const QHash<uint32_t, QList<uint64_t>> &formats)
+Swapchain *Window::swapchain(const std::shared_ptr<EglContext> &context, const QHash<uint32_t, QList<uint64_t>> &formats)
 {
     const QSize nativeSize = geometry().size() * devicePixelRatio();
+    const bool software = window()->surfaceType() == QSurface::RasterSurface; // RasterGLSurface is unsupported by us
     if (!m_swapchain || m_swapchain->size() != nativeSize
         || !formats.contains(m_swapchain->format())
-        || m_swapchain->modifiers() != formats[m_swapchain->format()]) {
-        const bool software = window()->surfaceType() == QSurface::RasterSurface; // RasterGLSurface is unsupported by us
+        || m_swapchain->modifiers() != formats[m_swapchain->format()]
+        || (!software && m_eglContext.lock() != context)) {
 
         GraphicsBufferAllocator *allocator;
         if (software) {
@@ -72,6 +73,7 @@ Swapchain *Window::swapchain(const QHash<uint32_t, QList<uint64_t>> &formats)
                     continue;
                 }
                 m_swapchain = std::make_unique<Swapchain>(allocator, options, buffer);
+                m_eglContext = context;
                 break;
             }
         }

src/plugins/qpa/window.h

@@ -16,6 +16,7 @@ namespace KWin
 {
 
 class InternalWindow;
+class EglContext;
 
 namespace QPA
 {
@@ -37,7 +38,7 @@ public:
     void requestActivateWindow() override;
 
     InternalWindow *internalWindow() const;
-    Swapchain *swapchain(const QHash<uint32_t, QList<uint64_t>> &formats);
+    Swapchain *swapchain(const std::shared_ptr<EglContext> &context, const QHash<uint32_t, QList<uint64_t>> &formats);
 
 private:
     void map();
@@ -46,6 +47,7 @@ private:
     QSurfaceFormat m_format;
     QPointer<InternalWindow> m_handle;
     std::unique_ptr<Swapchain> m_swapchain;
+    std::weak_ptr<EglContext> m_eglContext;
     quint32 m_windowId;
     qreal m_scale = 1;
 };