Merge branch 'master' into autoconf2

1 files changed, 12 insertions, 4 deletions

diff --git a/src/mesa/drivers/dri/intel/intel_buffer_objects.c b/src/mesa/drivers/dri/intel/intel_buffer_objects.c
index d93677bde2..89b489e28a 100644
--- a/src/mesa/drivers/dri/intel/intel_buffer_objects.c
+++ b/src/mesa/drivers/dri/intel/intel_buffer_objects.c
@@ -135,15 +135,23 @@ intel_bufferobj_data(GLcontext * ctx,
    if (intel_obj->region)
       intel_bufferobj_release_region(intel, intel_obj);
 
+   /* While it would seem to make sense to always reallocate the buffer here,
+    * since it should allow us better concurrency between rendering and
+    * map-cpu write-unmap, doing so was a minor (~10%) performance loss
+    * for both classic and TTM mode with openarena.  That may change with
+    * improved buffer manager algorithms.
+    */
    if (intel_obj->buffer != NULL && intel_obj->buffer->size != size) {
       dri_bo_unreference(intel_obj->buffer);
       intel_obj->buffer = NULL;
    }
+   if (size != 0) {
+      if (intel_obj->buffer == NULL)
+	 intel_bufferobj_alloc_buffer(intel, intel_obj);
 
-   intel_bufferobj_alloc_buffer(intel, intel_obj);
-
-   if (data != NULL)
-      dri_bo_subdata(intel_obj->buffer, 0, size, data);
+      if (data != NULL)
+	 dri_bo_subdata(intel_obj->buffer, 0, size, data);
+   }
 }