On Fri, Sep 06, 2013 at 09:24:16PM +0300, Alexandros Frantzis wrote: > Hi all, > > I have been working on eglCreateImageKHR for the Mir EGL platform in > Mesa, using gbm_bo as the "native pixmap" type (EGL_NATIVE_PIXMAP_KHR). > This is needed by nested Mir, but could also be useful in general. > > The current state of the (still very hacky) WIP can be found at: > > lp:~afrantzis/mir/spike-nested-gbm-egl-image-hack/ > > and > > http://paste.ubuntu.com/6071345/ > > (it is the diff against https://github.com/RAOF/mesa/ branch > egl-platform-mir) > > I have run into the following problem: when a client connects to the > nested mir server, it fails almost immediately because of what seems to > be a problem referencing a buffer that was created earlier. In > particular, we create gbm_bos (using GEM objects internally) for the > buffers backing the surface of the client, but, sometimes, when trying > to reference these GEM objects, e.g. when trying to create an EGLImage > for them we can't find them anymore! > > An interesting observation is that if the client submits the first 3 > buffers slowly (which trigger the gbm_bo creation and EGLImage > initialization and rendering on the server), the problem doesn't occur, > which indicates that there is some kind of synchronization problem. > > For anyone interested, things to try with the code above: > > !!! Make sure you run against the modified Mesa > (e.g. set your LD_LIBRARY_PATH) > > First run the host server: > $ sudo LD_LIBRARY_PATH=... bin/mir_demo_server_basic -f /tmp/mir_host > > Run the nested server: > $ sudo LD_LIBRARY_PATH=... bin/mir_demo_server_basic --nested-mode > /tmp/mir_host --enable-input off > > Run a normal client and watch the nested server crash: > $ sudo LD_LIBRARY_PATH=... bin/mir_demo_client_egltriangle > > Run an (initially) slow client and watch it work (I have modified this > example to start slow and speed up): > $ sudo LD_LIBRARY_PATH=... bin/mir_demo_client_scroll > > To aid the investigation I created a client that stresses multi-threaded > gbm_bo and EGLImage creation and rendering, trying to approximate nested > mir behavior, but I can't get it to fail! : > $ sudo LD_LIBRARY_PATH=... bin/mir_demo_client_egl_image -m /tmp/mir_host > > Thoughts welcome :) > > Note that I have only tried this on an Intel GPU. It would be interesting > to see if the behavior is different with Radeon or Nouveau.
Further investigation uncovered that this happens only when using PRIME fds in Mesa. Using GEM names works correctly. I have updated the branch lp:~afrantzis/mir/spike-nested-gbm-egl-image-hack/ to send both a PRIME fd and a GEM name for each buffer for testing purposes. The diff (against https://github.com/RAOF/mesa/) at: http://paste.ubuntu.com/6083139/ allows selecting which handle to use (set USE_PRIME in platform_mir.c to 0 to use GEM names). Thanks, Alexandros -- Mir-devel mailing list Mir-devel@lists.ubuntu.com Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/mir-devel
