Mesa (7.9): st/vega: Do not wait NULL fences.

[Chia-I Wu]

Module: Mesa
Branch: 7.9
Commit: 0d060d9933a7c42457eaaffe5e8430c8a1694b98
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=0d060d9933a7c42457eaaffe5e8430c8a1694b98

Author: Chia-I Wu <olv at lunarg.com>
Date:   Wed Nov 17 23:35:02 2010 +0800

st/vega: Do not wait NULL fences.
(cherry picked from commit cc5c908d7deab59f3512e1a5762fd058c4ae5940)

---

 src/gallium/state_trackers/vega/api_context.c |    7 ++++---
 1 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/src/gallium/state_trackers/vega/api_context.c b/src/gallium/state_trackers/vega/api_context.c
index 0d04d8e..d6bbda5 100644
--- a/src/gallium/state_trackers/vega/api_context.c
+++ b/src/gallium/state_trackers/vega/api_context.c
@@ -73,7 +73,8 @@ void vegaFinish(void)
    pipe = ctx->pipe;
 
    pipe->flush(pipe, PIPE_FLUSH_RENDER_CACHE | PIPE_FLUSH_FRAME, &fence);
-
-   pipe->screen->fence_finish(pipe->screen, fence, 0);
-   pipe->screen->fence_reference(pipe->screen, &fence, NULL);
+   if (fence) {
+      pipe->screen->fence_finish(pipe->screen, fence, 0);
+      pipe->screen->fence_reference(pipe->screen, &fence, NULL);
+   }
 }