private final void evalUpstreamSurface(String dbgPrefix, ProxySurface surface) {
    //
    // evaluate nature of upstreamSurface, may create EGL instances if required
    //

    boolean isEGLSurfaceValid = true; // assume yes

    final EGLGraphicsDevice eglDevice;
    final AbstractGraphicsConfiguration aConfig;
    {
      final AbstractGraphicsConfiguration surfaceConfig = surface.getGraphicsConfiguration();
      final AbstractGraphicsDevice surfaceDevice =
          null != surfaceConfig ? surfaceConfig.getScreen().getDevice() : null;
      if (DEBUG) {
        System.err.println(
            dbgPrefix
                + "SurfaceDevice: "
                + surfaceDevice.getClass().getSimpleName()
                + ", hash 0x"
                + Integer.toHexString(surfaceDevice.hashCode())
                + ", "
                + surfaceDevice);
        System.err.println(
            dbgPrefix
                + "SurfaceConfig: "
                + surfaceConfig.getClass().getSimpleName()
                + ", hash 0x"
                + Integer.toHexString(surfaceConfig.hashCode())
                + ", "
                + surfaceConfig);
      }

      final AbstractGraphicsConfiguration upstreamConfig =
          upstreamSurface.getGraphicsConfiguration();
      final AbstractGraphicsDevice upstreamDevice = upstreamConfig.getScreen().getDevice();
      if (DEBUG) {
        System.err.println(
            dbgPrefix
                + "UpstreamDevice: "
                + upstreamDevice.getClass().getSimpleName()
                + ", hash 0x"
                + Integer.toHexString(upstreamDevice.hashCode())
                + ", "
                + upstreamDevice);
        System.err.println(
            dbgPrefix
                + "UpstreamConfig: "
                + upstreamConfig.getClass().getSimpleName()
                + ", hash 0x"
                + Integer.toHexString(upstreamConfig.hashCode())
                + ", "
                + upstreamConfig);
      }

      if (surfaceDevice instanceof EGLGraphicsDevice) {
        eglDevice = (EGLGraphicsDevice) surfaceDevice;
        aConfig = surfaceConfig;
        if (DEBUG) {
          System.err.println(
              dbgPrefix
                  + "Reusing this eglDevice: "
                  + eglDevice
                  + ", using this config "
                  + aConfig.getClass().getSimpleName()
                  + " "
                  + aConfig);
        }
        if (EGL.EGL_NO_DISPLAY == eglDevice.getHandle()) {
          eglDevice.open();
          isEGLSurfaceValid = false;
          surface.addUpstreamOptionBits(ProxySurface.OPT_PROXY_OWNS_UPSTREAM_DEVICE);
        }
      } else if (upstreamDevice instanceof EGLGraphicsDevice) {
        eglDevice = (EGLGraphicsDevice) upstreamDevice;
        aConfig = upstreamConfig;
        if (DEBUG) {
          System.err.println(
              dbgPrefix
                  + "Reusing upstream eglDevice: "
                  + eglDevice
                  + ", using upstream config "
                  + aConfig.getClass().getSimpleName()
                  + " "
                  + aConfig);
        }
        if (EGL.EGL_NO_DISPLAY == eglDevice.getHandle()) {
          eglDevice.open();
          isEGLSurfaceValid = false;
          surface.addUpstreamOptionBits(ProxySurface.OPT_PROXY_OWNS_UPSTREAM_DEVICE);
        }
      } else {
        eglDevice = EGLDisplayUtil.eglCreateEGLGraphicsDevice(upstreamSurface);
        eglDevice.open();
        aConfig = upstreamConfig;
        isEGLSurfaceValid = false;
        surface.addUpstreamOptionBits(ProxySurface.OPT_PROXY_OWNS_UPSTREAM_DEVICE);
      }
    }

    final GLCapabilitiesImmutable capsRequested =
        (GLCapabilitiesImmutable) aConfig.getRequestedCapabilities();
    final EGLGraphicsConfiguration eglConfig;
    if (aConfig instanceof EGLGraphicsConfiguration) {
      // Config is already in EGL type - reuse ..
      final EGLGLCapabilities capsChosen = (EGLGLCapabilities) aConfig.getChosenCapabilities();
      if (!isEGLSurfaceValid
          || !EGLGraphicsConfiguration.isEGLConfigValid(
              eglDevice.getHandle(), capsChosen.getEGLConfig())) {
        // 'refresh' the native EGLConfig handle
        capsChosen.setEGLConfig(
            EGLGraphicsConfiguration.EGLConfigId2EGLConfig(
                eglDevice.getHandle(), capsChosen.getEGLConfigID()));
        if (0 == capsChosen.getEGLConfig()) {
          throw new GLException(
              "Refreshing native EGLConfig handle failed with error "
                  + EGLContext.toHexString(EGL.eglGetError())
                  + ": "
                  + eglDevice
                  + ", "
                  + capsChosen
                  + " of "
                  + aConfig);
        }
        final AbstractGraphicsScreen eglScreen =
            new DefaultGraphicsScreen(eglDevice, aConfig.getScreen().getIndex());
        eglConfig = new EGLGraphicsConfiguration(eglScreen, capsChosen, capsRequested, null);
        if (DEBUG) {
          System.err.println(dbgPrefix + "Refreshing eglConfig: " + eglConfig);
        }
        isEGLSurfaceValid = false;
      } else {
        eglConfig = (EGLGraphicsConfiguration) aConfig;
        if (DEBUG) {
          System.err.println(dbgPrefix + "Reusing eglConfig: " + eglConfig);
        }
      }
    } else {
      final AbstractGraphicsScreen eglScreen =
          new DefaultGraphicsScreen(eglDevice, aConfig.getScreen().getIndex());
      eglConfig =
          EGLGraphicsConfigurationFactory.chooseGraphicsConfigurationStatic(
              capsRequested,
              capsRequested,
              null,
              eglScreen,
              aConfig.getVisualID(VIDType.NATIVE),
              false /* forceTransparencyFlag */);

      if (null == eglConfig) {
        throw new GLException("Couldn't create EGLGraphicsConfiguration from " + eglScreen);
      } else if (DEBUG) {
        System.err.println(dbgPrefix + "Chosen eglConfig: " + eglConfig);
      }
      isEGLSurfaceValid = false;
    }
    surface.setGraphicsConfiguration(eglConfig);

    if (isEGLSurfaceValid) {
      isEGLSurfaceValid =
          EGLDrawable.isValidEGLSurface(eglDevice.getHandle(), upstreamSurface.getSurfaceHandle());
    }
    if (isEGLSurfaceValid) {
      surface.setSurfaceHandle(upstreamSurface.getSurfaceHandle());
      surface.clearUpstreamOptionBits(ProxySurface.OPT_PROXY_OWNS_UPSTREAM_SURFACE);
      if (DEBUG) {
        System.err.println(
            dbgPrefix + "Fin: Already valid EGL surface - use as-is: " + upstreamSurface);
      }
    } else {
      surface.setSurfaceHandle(EGL.EGL_NO_SURFACE);
      surface.addUpstreamOptionBits(
          ProxySurface.OPT_PROXY_OWNS_UPSTREAM_SURFACE); // create/destroy in EGLDrawable
      if (DEBUG) {
        System.err.println(dbgPrefix + "Fin: EGL surface n/a - TBD: " + upstreamSurface);
      }
    }
  }