A deadlock has been found, caused indirectly by the recent integration
of the STR (single-threaded rendering) changes for the OGL pipeline.
The deadlock only occurs when both OGL and Xinerama are enabled; see
attached thread dump. The following shows basically what is happening
to cause the deadlock. (The QFT is the one thread that processes all
OGL-related operations, including some GLXGraphicsConfig initialization.)

       XToolkit thread QueueFlusher thread
- handleConfigureNotifyEvent()
  - acquire AWT lock
    - checkIfOnNewScreen()
      - getDefaultConfiguration()
        - GLXGC.getConfig()
          - // init GLXGC on QFT
                                         - OGLRenderQueue.flushNow()
                                           - acquire AWT lock
                                             (but the lock has already
                                              been grabbed by the
                                              XToolkit thread, so
                                              deadlock)

So it should be noted that GLXGraphicsConfig initialization happens on a
different thread (the QFT), which tries to acquire the AWT lock. I'm
not that familiar with the code in
XDecoratedPeer.handleConfigureNotifyEvent(), but it seems dangerous to
have such a large synchronized() block around such complex code.
###@###.### 2005-04-01 01:36:52 GMT