st/mesa: use asynchronous flushes (TODO)

TODO: It looks like si_fence_server_sync still isn't strict enough
for unflushed fences.

2 files changed, 26 insertions, 4 deletions

diff --git a/src/mesa/state_tracker/st_cb_flush.c b/src/mesa/state_tracker/st_cb_flush.c
index c8452d0e6f..5f4e2ac3cc 100644
--- a/src/mesa/state_tracker/st_cb_flush.c
+++ b/src/mesa/state_tracker/st_cb_flush.c
@@ -63,7 +63,7 @@ void st_finish( struct st_context *st )
 {
    struct pipe_fence_handle *fence = NULL;
 
-   st_flush(st, &fence, 0);
+   st_flush(st, &fence, PIPE_FLUSH_ASYNC | PIPE_FLUSH_HINT_FINISH);
 
    if(fence) {
       st->pipe->screen->fence_finish(st->pipe->screen, NULL, fence,
@@ -88,7 +88,7 @@ static void st_glFlush(struct gl_context *ctx)
     * synchronization issues.  Calling finish() here will just hide
     * problems that need to be fixed elsewhere.
     */
-   st_flush(st, NULL, 0);
+   st_flush(st, NULL, PIPE_FLUSH_ASYNC);
 
    st_manager_flush_frontbuffer(st);
 }
diff --git a/src/mesa/state_tracker/st_cb_syncobj.c b/src/mesa/state_tracker/st_cb_syncobj.c
index 637fbe3b73..44323b4750 100644
--- a/src/mesa/state_tracker/st_cb_syncobj.c
+++ b/src/mesa/state_tracker/st_cb_syncobj.c
@@ -130,8 +130,30 @@ static void st_server_wait_sync(struct gl_context *ctx,
                                 struct gl_sync_object *obj,
                                 GLbitfield flags, GLuint64 timeout)
 {
-   /* NO-OP.
-    * Neither Gallium nor DRM interfaces support blocking on the GPU. */
+   struct pipe_context *pipe = st_context(ctx)->pipe;
+   struct pipe_screen *screen = pipe->screen;
+   struct st_sync_object *so = (struct st_sync_object*)obj;
+   struct pipe_fence_handle *fence = NULL;
+
+   /* Nothing needs to be done here if the driver does not support async
+    * flushes. */
+   if (!pipe->fence_server_sync)
+      return;
+
+   /* If the fence doesn't exist, assume it's signalled. */
+   mtx_lock(&so->mutex);
+   if (!so->fence) {
+      mtx_unlock(&so->mutex);
+      so->b.StatusFlag = GL_TRUE;
+      return;
+   }
+
+   /* We need a local copy of the fence pointer. */
+   screen->fence_reference(screen, &fence, so->fence);
+   mtx_unlock(&so->mutex);
+
+   pipe->fence_server_sync(pipe, fence);
+   screen->fence_reference(screen, &fence, NULL);
 }
 
 void st_init_syncobj_functions(struct dd_function_table *functions)