From a945e203d4fe254593bc0c5c5d6caca45e65f9f7 Mon Sep 17 00:00:00 2001
From: Eric Anholt <eric@anholt.net>
Date: Tue, 2 Jun 2009 06:53:40 -0700
Subject: [PATCH] i915: Don't put VBOs in graphics memory unless required for
 an operation.

This saves doing swtnl from uncached memory, which is painful.  Improves
clutter test-text performance by 10% since it started using VBOs.
---
 .../drivers/dri/intel/intel_buffer_objects.c  | 39 ++++++++++++++++++-
 .../drivers/dri/intel/intel_buffer_objects.h  |  2 +
 2 files changed, 40 insertions(+), 1 deletion(-)

diff --git a/src/mesa/drivers/dri/intel/intel_buffer_objects.c b/src/mesa/drivers/dri/intel/intel_buffer_objects.c
index 0db1f392c0a..23ba3b9ef67 100644
--- a/src/mesa/drivers/dri/intel/intel_buffer_objects.c
+++ b/src/mesa/drivers/dri/intel/intel_buffer_objects.c
@@ -111,6 +111,7 @@ intel_bufferobj_free(GLcontext * ctx, struct gl_buffer_object *obj)
    if (obj->Pointer)
       intel_bufferobj_unmap(ctx, 0, obj);
 
+   _mesa_free(intel_obj->sys_buffer);
    if (intel_obj->region) {
       intel_bufferobj_release_region(intel, intel_obj);
    }
@@ -151,7 +152,23 @@ intel_bufferobj_data(GLcontext * ctx,
       dri_bo_unreference(intel_obj->buffer);
       intel_obj->buffer = NULL;
    }
+   _mesa_free(intel_obj->sys_buffer);
+   intel_obj->sys_buffer = NULL;
+
    if (size != 0) {
+#ifdef I915
+      /* On pre-965, stick VBOs in system memory, as we're always doing swtnl
+       * with their contents anyway.
+       */
+      if (target == GL_ARRAY_BUFFER || target == GL_ELEMENT_ARRAY_BUFFER) {
+	 intel_obj->sys_buffer = _mesa_malloc(size);
+	 if (intel_obj->sys_buffer != NULL) {
+	    if (data != NULL)
+	       memcpy(intel_obj->sys_buffer, data, size);
+	    return;
+	 }
+      }
+#endif
       intel_bufferobj_alloc_buffer(intel, intel_obj);
 
       if (data != NULL)
@@ -181,7 +198,10 @@ intel_bufferobj_subdata(GLcontext * ctx,
    if (intel_obj->region)
       intel_bufferobj_cow(intel, intel_obj);
 
-   dri_bo_subdata(intel_obj->buffer, offset, size, data);
+   if (intel_obj->sys_buffer)
+      memcpy((char *)intel_obj->sys_buffer + offset, data, size);
+   else
+      dri_bo_subdata(intel_obj->buffer, offset, size, data);
 }
 
 
@@ -218,6 +238,11 @@ intel_bufferobj_map(GLcontext * ctx,
 
    assert(intel_obj);
 
+   if (intel_obj->sys_buffer) {
+      obj->Pointer = intel_obj->sys_buffer;
+      return obj->Pointer;
+   }
+
    if (intel_obj->region)
       intel_bufferobj_cow(intel, intel_obj);
 
@@ -274,6 +299,18 @@ intel_bufferobj_buffer(struct intel_context *intel,
       }
    }
 
+   if (intel_obj->buffer == NULL) {
+      intel_bufferobj_alloc_buffer(intel, intel_obj);
+      intel_bufferobj_subdata(&intel->ctx,
+			      GL_ARRAY_BUFFER_ARB,
+			      0,
+			      intel_obj->Base.Size,
+			      intel_obj->sys_buffer,
+			      &intel_obj->Base);
+      _mesa_free(intel_obj->sys_buffer);
+      intel_obj->sys_buffer = NULL;
+   }
+
    return intel_obj->buffer;
 }
 
diff --git a/src/mesa/drivers/dri/intel/intel_buffer_objects.h b/src/mesa/drivers/dri/intel/intel_buffer_objects.h
index 7ef723833c0..04310156319 100644
--- a/src/mesa/drivers/dri/intel/intel_buffer_objects.h
+++ b/src/mesa/drivers/dri/intel/intel_buffer_objects.h
@@ -42,6 +42,8 @@ struct intel_buffer_object
 {
    struct gl_buffer_object Base;
    dri_bo *buffer;     /* the low-level buffer manager's buffer handle */
+   /** System memory buffer data, if not using a BO to store the data. */
+   void *sys_buffer;
 
    struct intel_region *region; /* Is there a zero-copy texture
                                    associated with this (pixel)
-- 
2.30.2