Disable switchable widget compositing when using XCB in Parallels VM

The Parallels 3D hardware acceleration does not seem to play nice with
Qt Creator when switching between tabs that have OpenGL Qt Quick Content
and those that have just raster widget content.  QWidgetBackingstore has
the ability to switch how content is flushed depending on if the
SwitchableWidgetComposition capability is available.  Previously for XCB
it was always enabled, but should be disabled when using the GLX
integration for the Parallels VM.

Change-Id: I42e41456e0873f6780f5d0333dbfaaf8fcce4a5e
Task-number: QTCREATORBUG-16742
Reviewed-by: Laszlo Agocs <laszlo.agocs@qt.io>

4 files changed, 25 insertions, 1 deletions

diff --git a/src/plugins/platforms/xcb/gl_integrations/qxcbglintegration.h b/src/plugins/platforms/xcb/gl_integrations/qxcbglintegration.h
index 74c117582a..e023833826 100644
--- a/src/plugins/platforms/xcb/gl_integrations/qxcbglintegration.h
+++ b/src/plugins/platforms/xcb/gl_integrations/qxcbglintegration.h
@@ -54,6 +54,7 @@ public:
     virtual bool initialize(QXcbConnection *connection) = 0;
 
     virtual bool supportsThreadedOpenGL() const { return false; }
+    virtual bool supportsSwitchableWidgetComposition()  const { return true; }
     virtual bool handleXcbEvent(xcb_generic_event_t *event, uint responseType);
 
     virtual QXcbWindow *createWindow(QWindow *window) const = 0;
diff --git a/src/plugins/platforms/xcb/gl_integrations/xcb_glx/qxcbglxintegration.cpp b/src/plugins/platforms/xcb/gl_integrations/xcb_glx/qxcbglxintegration.cpp
index 55d0ff38b7..d49739159a 100644
--- a/src/plugins/platforms/xcb/gl_integrations/xcb_glx/qxcbglxintegration.cpp
+++ b/src/plugins/platforms/xcb/gl_integrations/xcb_glx/qxcbglxintegration.cpp
@@ -218,5 +218,26 @@ bool QXcbGlxIntegration::supportsThreadedOpenGL() const
     return QGLXContext::supportsThreading();
 }
 
+bool QXcbGlxIntegration::supportsSwitchableWidgetComposition() const
+{
+    static bool vendorChecked = false;
+    static bool isSwitchableWidgetCompositionAvailable = true;
+    if (!vendorChecked) {
+        vendorChecked = true;
+        Display *display = glXGetCurrentDisplay();
+#ifdef XCB_USE_XLIB
+        if (!display)
+            display = static_cast<Display *>(m_connection->xlib_display());
+#endif
+        const char *glxvendor = glXGetClientString(display, GLX_VENDOR);
+        if (glxvendor) {
+            if (!strcmp(glxvendor, "Parallels Inc"))
+                isSwitchableWidgetCompositionAvailable = false;
+        }
+    }
+
+    return isSwitchableWidgetCompositionAvailable;
+}
+
 
 QT_END_NAMESPACE
diff --git a/src/plugins/platforms/xcb/gl_integrations/xcb_glx/qxcbglxintegration.h b/src/plugins/platforms/xcb/gl_integrations/xcb_glx/qxcbglxintegration.h
index 4366d07b42..7212fcf3ed 100644
--- a/src/plugins/platforms/xcb/gl_integrations/xcb_glx/qxcbglxintegration.h
+++ b/src/plugins/platforms/xcb/gl_integrations/xcb_glx/qxcbglxintegration.h
@@ -54,6 +54,7 @@ public:
     QPlatformOffscreenSurface *createPlatformOffscreenSurface(QOffscreenSurface *surface) const Q_DECL_OVERRIDE;
 
     virtual bool supportsThreadedOpenGL() const Q_DECL_OVERRIDE;
+    virtual bool supportsSwitchableWidgetComposition() const Q_DECL_OVERRIDE;
 
 private:
     QXcbConnection *m_connection;
diff --git a/src/plugins/platforms/xcb/qxcbintegration.cpp b/src/plugins/platforms/xcb/qxcbintegration.cpp
index 94e17a2983..513498ee5f 100644
--- a/src/plugins/platforms/xcb/qxcbintegration.cpp
+++ b/src/plugins/platforms/xcb/qxcbintegration.cpp
@@ -254,7 +254,8 @@ bool QXcbIntegration::hasCapability(QPlatformIntegration::Capability cap) const
     case ForeignWindows: return true;
     case SyncState: return true;
     case RasterGLSurface: return true;
-    case SwitchableWidgetComposition: return true;
+    case SwitchableWidgetComposition: return m_connections.at(0)->glIntegration()
+                                          && m_connections.at(0)->glIntegration()->supportsSwitchableWidgetComposition();
     default: return QPlatformIntegration::hasCapability(cap);
     }
 }