2 files changed, 28 insertions, 20 deletions

diff --git a/src/gallium/drivers/r600/compute_memory_pool.c b/src/gallium/drivers/r600/compute_memory_pool.c
index 9cb16f8c29e..fe19d9ef81c 100644
--- a/src/gallium/drivers/r600/compute_memory_pool.c
+++ b/src/gallium/drivers/r600/compute_memory_pool.c
@@ -353,19 +353,21 @@ int compute_memory_promote_item(struct compute_memory_pool *pool,
 	list_add(&item->link, pos);
 	item->start_in_dw = start_in_dw;
 
-	u_box_1d(0, item->size_in_dw * 4, &box);
-
-	rctx->b.b.resource_copy_region(pipe,
-			dst, 0, item->start_in_dw * 4, 0 ,0,
-			src, 0, &box);
-
-	/* We check if the item is mapped for reading.
-	 * In this case, we need to keep the temporary buffer 'alive'
-	 * because it is possible to keep a map active for reading
-	 * while a kernel (that reads from it) executes */
-	if (!(item->status & ITEM_MAPPED_FOR_READING)) {
-		pool->screen->b.b.resource_destroy(screen, src);
-		item->real_buffer = NULL;
+	if (src != NULL) {
+		u_box_1d(0, item->size_in_dw * 4, &box);
+
+		rctx->b.b.resource_copy_region(pipe,
+				dst, 0, item->start_in_dw * 4, 0 ,0,
+				src, 0, &box);
+
+		/* We check if the item is mapped for reading.
+		 * In this case, we need to keep the temporary buffer 'alive'
+		 * because it is possible to keep a map active for reading
+		 * while a kernel (that reads from it) executes */
+		if (!(item->status & ITEM_MAPPED_FOR_READING)) {
+			pool->screen->b.b.resource_destroy(screen, src);
+			item->real_buffer = NULL;
+		}
 	}
 
 	return 0;
@@ -475,8 +477,7 @@ struct compute_memory_item* compute_memory_alloc(
 	new_item->start_in_dw = -1; /* mark pending */
 	new_item->id = pool->next_id++;
 	new_item->pool = pool;
-	new_item->real_buffer = (struct r600_resource*)r600_compute_buffer_alloc_vram(
-							pool->screen, size_in_dw * 4);
+	new_item->real_buffer = NULL;
 
 	list_addtail(&new_item->link, pool->unallocated_list);
 
diff --git a/src/gallium/drivers/r600/evergreen_compute.c b/src/gallium/drivers/r600/evergreen_compute.c
index 5c115dcb282..12e9c85586d 100644
--- a/src/gallium/drivers/r600/evergreen_compute.c
+++ b/src/gallium/drivers/r600/evergreen_compute.c
@@ -970,14 +970,21 @@ void *r600_compute_global_transfer_map(
 	struct r600_resource_global* buffer =
 		(struct r600_resource_global*)resource;
 
-	struct pipe_resource *dst;
+	struct compute_memory_item *item = buffer->chunk;
+	struct pipe_resource *dst = NULL;
 	unsigned offset = box->x;
 
-	if (is_item_in_pool(buffer->chunk)) {
-		compute_memory_demote_item(pool, buffer->chunk, ctx_);
+	if (is_item_in_pool(item)) {
+		compute_memory_demote_item(pool, item, ctx_);
+	}
+	else {
+		if (item->real_buffer == NULL) {
+			item->real_buffer = (struct r600_resource*)
+					r600_compute_buffer_alloc_vram(pool->screen, item->size_in_dw * 4);
+		}
 	}
 
-	dst = (struct pipe_resource*)buffer->chunk->real_buffer;
+	dst = (struct pipe_resource*)item->real_buffer;
 
 	if (usage & PIPE_TRANSFER_READ)
 		buffer->chunk->status |= ITEM_MAPPED_FOR_READING;
@@ -988,7 +995,7 @@ void *r600_compute_global_transfer_map(
 			box->x, box->y, box->z, box->width, box->height,
 			box->depth);
 	COMPUTE_DBG(rctx->screen, "Buffer id = %u offset = "
-		"%u (box.x)\n", buffer->chunk->id, box->x);
+		"%u (box.x)\n", item->id, box->x);
 
 
 	assert(resource->target == PIPE_BUFFER);