Mesa (master): svga: fix crash when clearing null color buffer

[Brian Paul]

Module: Mesa
Branch: master
Commit: 3618ac4f202138079024ea6ed2cf7e2ef5463066
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=3618ac4f202138079024ea6ed2cf7e2ef5463066

Author: Brian Paul <brianp at vmware.com>
Date:   Thu Jan 16 13:53:27 2014 -0800

svga: fix crash when clearing null color buffer

Fixes regression since 9baa45f78b8ca7d66280e36009b6a685055d7cd6
but some of the piglit fbo-drawbuffers-none tests still don't
pass.

v2: use the right pointer type for 'h'

Reviewed-by: José Fonseca <jfonseca at vmware.com>

---

 src/gallium/drivers/svga/svga_pipe_clear.c |   10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/src/gallium/drivers/svga/svga_pipe_clear.c b/src/gallium/drivers/svga/svga_pipe_clear.c
index 47f6258..5deebb2 100644
--- a/src/gallium/drivers/svga/svga_pipe_clear.c
+++ b/src/gallium/drivers/svga/svga_pipe_clear.c
@@ -111,9 +111,13 @@ svga_clear(struct pipe_context *pipe, unsigned buffers,
    struct svga_context *svga = svga_context( pipe );
    enum pipe_error ret;
 
-   if (buffers & PIPE_CLEAR_COLOR)
-      SVGA_DBG(DEBUG_DMA, "clear sid %p\n",
-               svga_surface(svga->curr.framebuffer.cbufs[0])->handle);
+   if (buffers & PIPE_CLEAR_COLOR) {
+      struct svga_winsys_surface *h = NULL;
+      if (svga->curr.framebuffer.cbufs[0]) {
+         h = svga_surface(svga->curr.framebuffer.cbufs[0])->handle;
+      }
+      SVGA_DBG(DEBUG_DMA, "clear sid %p\n", h);
+   }
 
    /* flush any queued prims (don't want them to appear after the clear!) */
    svga_hwtnl_flush_retry(svga);