VAAPI: vaQuerySurfaceStatus() is totally unreliable.

The first time befor a surface is used it will return VASurfaceReady.
However whenever it has been used it status is ALWAYS VASurfaceRendering,
therefor it is unusable as a guard against selecting a surface that is
being used for rendering or displaying.

modules/codec/avcodec/va.c

@@ -289,7 +289,8 @@ static void destroy_surfaces( vlc_va_conn_t *conn )
             abort();
         }
 
-        surface->i_refcount --;
+        if( surface->i_refcount > 0 )
+            surface->i_refcount --;
         assert(surface->i_refcount == 0);
 
         vaDestroySurfaces( conn->p_display, &surface->i_id, 1 );
@@ -310,25 +311,18 @@ static vlc_va_surface_t *get_surface(vlc_va_conn_t *conn)
     assert( conn->pool.count > 0 );
     assert( conn->pool.p_surfaces );
 
-    unsigned int next = conn->pool.current;
+    unsigned int next = (conn->pool.current + 1) % conn->pool.count;
     unsigned int tries = 0;
-    while (tries < conn->pool.count)
+    while(tries < conn->pool.count)
     {
-        VAStatus status;
-        VASurfaceStatus ready;
         vlc_va_surface_t *surface;
-
         surface = &conn->pool.p_surfaces[next];
 
         vlc_mutex_lock(&surface->lock);
-        VASurfaceID id = surface->i_id;
-        status = vaQuerySurfaceStatus(conn->p_display, id, &ready);
-        if ((status == VA_STATUS_SUCCESS) &&
-            (ready == VASurfaceReady) &&
-            (surface->i_refcount == 0))
+        if (surface->i_refcount == 0)
         {
             surface->i_refcount++;
-            conn->pool.current = (next + 1) % conn->pool.count;
+            conn->pool.current = next;
             vlc_mutex_unlock(&surface->lock);
             return surface;
         }
@@ -351,16 +345,8 @@ static void release_surface(vlc_va_conn_t *conn, vlc_va_surface_t *surface)
     if (surface->i_refcount == 0)
         abort();
 
-    VAStatus status;
-    VASurfaceStatus ready;
-    VASurfaceID id = surface->i_id;
-    status = vaQuerySurfaceStatus(conn->p_display, id, &ready);
-    if ((status == VA_STATUS_SUCCESS) &&
-        (ready == VASurfaceReady))
-    {
-        surface->i_refcount--;
-        assert(surface->i_refcount == 0);
-    }
+    surface->i_refcount--;
+    assert(surface->i_refcount == 0);
     vlc_mutex_unlock(&surface->lock);
 }