Mesa (7.10): i965: Fix occlusion query on sandybridge

[Zhenyu Wang]

Module: Mesa
Branch: 7.10
Commit: 96685a662f5f3e980895fa8589fd486903852537
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=96685a662f5f3e980895fa8589fd486903852537

Author: Zhenyu Wang <zhenyuw at linux.intel.com>
Date:   Tue Dec 28 11:03:45 2010 +0800

i965: Fix occlusion query on sandybridge

Clear target query buffer fixed occlusion query on sandybridge.

https://bugs.freedesktop.org/show_bug.cgi?id=32167
(cherry picked from commit 689aca782216d2666486dea02206cbc9c4162e0d)

---

 src/mesa/drivers/dri/i965/brw_queryobj.c |    6 ++++++
 1 files changed, 6 insertions(+), 0 deletions(-)

diff --git a/src/mesa/drivers/dri/i965/brw_queryobj.c b/src/mesa/drivers/dri/i965/brw_queryobj.c
index f28f286..656aad6 100644
--- a/src/mesa/drivers/dri/i965/brw_queryobj.c
+++ b/src/mesa/drivers/dri/i965/brw_queryobj.c
@@ -232,6 +232,12 @@ brw_prepare_query_begin(struct brw_context *brw)
       brw->query.bo = NULL;
 
       brw->query.bo = drm_intel_bo_alloc(intel->bufmgr, "query", 4096, 1);
+
+      /* clear target buffer */
+      drm_intel_bo_map(brw->query.bo, GL_TRUE);
+      memset((char *)brw->query.bo->virtual, 0, 4096);
+      drm_intel_bo_unmap(brw->query.bo);
+
       brw->query.index = 0;
    }