Better handling of GLX / EGL errors.

If context creation fails, try again without a shared context. Added
QPlatformOpenGLContext::isSharing() and
QPlatformOpenGLContext::isValid() to propagate whether the platform
context was successfully created with or without sharing.

Change-Id: I37080b645f531fd207946441057be6d3f6be3f6e
Reviewed-by: Jørgen Lind <jorgen.lind@nokia.com>

src/gui/kernel/qopenglcontext.cpp

@@ -164,6 +164,8 @@ bool QOpenGLContext::create()
     Q_D(QOpenGLContext);
     d->platformGLContext = QGuiApplicationPrivate::platformIntegration()->createPlatformOpenGLContext(this);
     d->platformGLContext->setContext(this);
+    if (!d->platformGLContext->isSharing())
+        d->shareContext = 0;
     d->shareGroup = d->shareContext ? d->shareContext->shareGroup() : new QOpenGLContextGroup;
     d->shareGroup->d_func()->addContext(this);
     return d->platformGLContext;
@@ -197,7 +199,7 @@ QOpenGLContext::~QOpenGLContext()
 bool QOpenGLContext::isValid() const
 {
     Q_D(const QOpenGLContext);
-    return d->platformGLContext != 0;
+    return d->platformGLContext && d->platformGLContext->isValid();
 }
 
 /*!
@@ -225,7 +227,7 @@ QOpenGLFunctions *QOpenGLContext::functions() const
 bool QOpenGLContext::makeCurrent(QSurface *surface)
 {
     Q_D(QOpenGLContext);
-    if (!d->platformGLContext)
+    if (!isValid())
         return false;
 
     if (thread() != QThread::currentThread())
@@ -257,7 +259,7 @@ bool QOpenGLContext::makeCurrent(QSurface *surface)
 void QOpenGLContext::doneCurrent()
 {
     Q_D(QOpenGLContext);
-    if (!d->platformGLContext)
+    if (!isValid())
         return;
 
     if (QOpenGLContext::currentContext() == this)
@@ -282,7 +284,7 @@ QSurface *QOpenGLContext::surface() const
 void QOpenGLContext::swapBuffers(QSurface *surface)
 {
     Q_D(QOpenGLContext);
-    if (!d->platformGLContext)
+    if (!isValid())
         return;
 
     if (!surface) {

src/gui/kernel/qplatformopenglcontext_qpa.h

@@ -68,6 +68,9 @@ public:
     virtual bool makeCurrent(QPlatformSurface *surface) = 0;
     virtual void doneCurrent() = 0;
 
+    virtual bool isSharing() const { return false; }
+    virtual bool isValid() const { return true; }
+
     virtual QFunctionPointer getProcAddress(const QByteArray &procName) = 0;
 
     QOpenGLContext *context() const;

src/platformsupport/eglconvenience/qeglplatformcontext.cpp

@@ -56,7 +56,7 @@ QEGLPlatformContext::QEGLPlatformContext(const QSurfaceFormat &format, QPlatform
     EGLConfig config = q_configFromGLFormat(display, format, true);
     m_format = q_glFormatFromConfig(display, config);
 
-    EGLContext shareContext = share ? static_cast<QEGLPlatformContext *>(share)->m_eglContext : 0;
+    m_shareContext = share ? static_cast<QEGLPlatformContext *>(share)->m_eglContext : 0;
 
     QVector<EGLint> contextAttrs;
     contextAttrs.append(EGL_CONTEXT_CLIENT_VERSION);
@@ -64,11 +64,10 @@ QEGLPlatformContext::QEGLPlatformContext(const QSurfaceFormat &format, QPlatform
     contextAttrs.append(EGL_NONE);
 
     eglBindAPI(m_eglApi);
-    m_eglContext = eglCreateContext(m_eglDisplay, config, shareContext, contextAttrs.constData());
-    if (m_eglContext == EGL_NO_CONTEXT) {
-        qWarning("Could not create the egl context\n");
-        eglTerminate(m_eglDisplay);
-        qFatal("EGL error");
+    m_eglContext = eglCreateContext(m_eglDisplay, config, m_shareContext, contextAttrs.constData());
+    if (m_eglContext == EGL_NO_CONTEXT && m_shareContext != EGL_NO_CONTEXT) {
+        m_shareContext = 0;
+        m_eglContext = eglCreateContext(m_eglDisplay, config, 0, contextAttrs.constData());
     }
 }
 

src/platformsupport/eglconvenience/qeglplatformcontext_p.h

@@ -59,6 +59,8 @@ public:
     void (*getProcAddress(const QByteArray &procName)) ();
 
     QSurfaceFormat format() const;
+    bool isSharing() const { return m_shareContext != EGL_NO_CONTEXT; }
+    bool isValid() const { return m_eglContext != EGL_NO_CONTEXT; }
 
     EGLContext eglContext() const;
 
@@ -67,6 +69,7 @@ protected:
 
 private:
     EGLContext m_eglContext;
+    EGLContext m_shareContext;
     EGLDisplay m_eglDisplay;
     EGLenum m_eglApi;
 

src/plugins/platforms/xcb/qglxintegration.cpp

@@ -65,13 +65,21 @@ QGLXContext::QGLXContext(QXcbScreen *screen, const QSurfaceFormat &format, QPlat
     , m_screen(screen)
     , m_context(0)
 {
-    GLXContext shareGlxContext = 0;
+    m_shareContext = 0;
     if (share)
-        shareGlxContext = static_cast<const QGLXContext*>(share)->glxContext();
+        m_shareContext = static_cast<const QGLXContext*>(share)->glxContext();
 
     GLXFBConfig config = qglx_findConfig(DISPLAY_FROM_XCB(screen),screen->screenNumber(),format);
-    m_context = glXCreateNewContext(DISPLAY_FROM_XCB(screen), config, GLX_RGBA_TYPE, shareGlxContext, TRUE);
-    m_format = qglx_surfaceFormatFromGLXFBConfig(DISPLAY_FROM_XCB(screen), config, m_context);
+
+    m_context = glXCreateNewContext(DISPLAY_FROM_XCB(screen), config, GLX_RGBA_TYPE, m_shareContext, TRUE);
+    if (!m_context && m_shareContext) {
+        // re-try without a shared glx context
+        m_shareContext = 0;
+        m_context = glXCreateNewContext(DISPLAY_FROM_XCB(screen), config, GLX_RGBA_TYPE, 0, TRUE);
+    }
+
+    if (m_context)
+        m_format = qglx_surfaceFormatFromGLXFBConfig(DISPLAY_FROM_XCB(screen), config, m_context);
 }
 
 QGLXContext::~QGLXContext()
@@ -137,4 +145,14 @@ QSurfaceFormat QGLXContext::format() const
     return m_format;
 }
 
+bool QGLXContext::isSharing() const
+{
+    return m_shareContext != 0;
+}
+
+bool QGLXContext::isValid() const
+{
+    return m_context != 0;
+}
+
 QT_END_NAMESPACE

src/plugins/platforms/xcb/qglxintegration.h

@@ -66,12 +66,15 @@ public:
     void (*getProcAddress(const QByteArray &procName)) ();
 
     QSurfaceFormat format() const;
+    bool isSharing() const;
+    bool isValid() const;
 
     GLXContext glxContext() const { return m_context; }
 
 private:
     QXcbScreen *m_screen;
     GLXContext m_context;
+    GLXContext m_shareContext;
     QSurfaceFormat m_format;
 };
 

src/plugins/platforms/xcb/qxcbconnection.cpp

@@ -86,6 +86,11 @@ extern "C" {
 
 QT_BEGIN_NAMESPACE
 
+static int nullErrorHandler(Display *, XErrorEvent *)
+{
+    return 0;
+}
+
 QXcbConnection::QXcbConnection(const char *displayName)
     : m_displayName(displayName ? QByteArray(displayName) : qgetenv("DISPLAY"))
 #ifdef XCB_USE_XINPUT2_MAEMO
@@ -106,6 +111,7 @@ QXcbConnection::QXcbConnection(const char *displayName)
     m_primaryScreen = DefaultScreen(dpy);
     m_connection = XGetXCBConnection(dpy);
     XSetEventQueueOwner(dpy, XCBOwnsEventQueue);
+    XSetErrorHandler(nullErrorHandler);
     m_xlib_display = dpy;
 #ifdef XCB_USE_EGL
     EGLDisplay eglDisplay = eglGetDisplay(dpy);
@@ -1002,7 +1008,6 @@ void QXcbConnection::initializeXFixes()
         xfixes_first_event = 0;
     }
     free(xfixes_query);
-
 }
 
 void QXcbConnection::initializeXRender()