3 files changed, 37 insertions, 12 deletions

diff --git a/src/mesa/main/mtypes.h b/src/mesa/main/mtypes.h
index f906de8357e..baf5850b83b 100644
--- a/src/mesa/main/mtypes.h
+++ b/src/mesa/main/mtypes.h
@@ -1499,6 +1499,8 @@ struct gl_buffer_object
    GLenum Usage;
    GLenum Access;
    GLvoid *Pointer;          /**< Only valid while buffer is mapped */
+   GLintptr Offset;          /**< mapped offset */
+   GLsizeiptr Length;        /**< mapped length */
    GLsizeiptrARB Size;       /**< Size of storage in bytes */
    GLubyte *Data;            /**< Location of storage either in RAM or VRAM. */
    GLboolean OnCard;         /**< Is buffer in VRAM? (hardware drivers) */
diff --git a/src/mesa/state_tracker/st_cb_bufferobjects.c b/src/mesa/state_tracker/st_cb_bufferobjects.c
index 45fbe8c76e0..3651e4ae7dc 100644
--- a/src/mesa/state_tracker/st_cb_bufferobjects.c
+++ b/src/mesa/state_tracker/st_cb_bufferobjects.c
@@ -201,6 +201,10 @@ st_bufferobj_map(GLcontext *ctx, GLenum target, GLenum access,
    }
 
    obj->Pointer = pipe_buffer_map(pipe->screen, st_obj->buffer, flags);
+   if(obj->Pointer) {
+      obj->Offset = 0;
+      obj->Length = obj->Size;
+   }
    return obj->Pointer;
 }
 
@@ -231,11 +235,18 @@ st_bufferobj_map_range(GLcontext *ctx, GLenum target,
    if (access & MESA_MAP_NOWAIT_BIT)
       flags |= PIPE_BUFFER_USAGE_DONTBLOCK;
 
-   map = pipe_buffer_map_range(pipe->screen, st_obj->buffer, offset, length, flags);
-   /* this is expected to point to the buffer start, in order to calculate the
-    * vertices offsets 
-    */
-   obj->Pointer = map ? map - offset : NULL;
+   assert(offset >= 0);
+   assert(length >= 0);
+   assert(offset < obj->Size);
+   assert(offset + length <= obj->Size);
+
+   map = obj->Pointer = pipe_buffer_map_range(pipe->screen, st_obj->buffer, offset, length, flags);
+   if(obj->Pointer) {
+      obj->Offset = 0;
+      obj->Length = obj->Size;
+      map += offset;
+   }
+   
    return map;
 }
 
@@ -248,7 +259,14 @@ st_bufferobj_flush_mapped_range(GLcontext *ctx, GLenum target,
    struct pipe_context *pipe = st_context(ctx)->pipe;
    struct st_buffer_object *st_obj = st_buffer_object(obj);
 
-   pipe_buffer_flush_mapped_range(pipe->screen, st_obj->buffer, offset, length);
+   /* Subrange is relative to mapped range */
+   assert(offset >= 0);
+   assert(length >= 0);
+   assert(offset < obj->Length);
+   assert(offset + length <= obj->Length);
+   
+   pipe_buffer_flush_mapped_range(pipe->screen, st_obj->buffer, 
+                                  obj->Offset + offset, length);
 }
 
 
@@ -263,6 +281,8 @@ st_bufferobj_unmap(GLcontext *ctx, GLenum target, struct gl_buffer_object *obj)
 
    pipe_buffer_unmap(pipe->screen, st_obj->buffer);
    obj->Pointer = NULL;
+   obj->Offset = 0;
+   obj->Length = 0;
    return GL_TRUE;
 }
 
diff --git a/src/mesa/vbo/vbo_exec_draw.c b/src/mesa/vbo/vbo_exec_draw.c
index 6f8d1f8eb07..b3787459169 100644
--- a/src/mesa/vbo/vbo_exec_draw.c
+++ b/src/mesa/vbo/vbo_exec_draw.c
@@ -240,13 +240,16 @@ static void vbo_exec_vtx_unmap( struct vbo_exec_context *exec )
 
    if (exec->vtx.bufferobj->Name) {
       GLcontext *ctx = exec->ctx;
-      GLintptr offset = exec->vtx.buffer_used;
-      GLsizeiptr length = (exec->vtx.buffer_ptr - exec->vtx.buffer_map) * sizeof(float);
       
-      if(ctx->Driver.FlushMappedBufferRange)
-         ctx->Driver.FlushMappedBufferRange(ctx, target,
-                                            offset, length,
-                                            exec->vtx.bufferobj);
+      if(ctx->Driver.FlushMappedBufferRange) {
+         GLintptr offset = exec->vtx.buffer_used - exec->vtx.bufferobj->Offset;
+         GLsizeiptr length = (exec->vtx.buffer_ptr - exec->vtx.buffer_map) * sizeof(float);
+
+         if(length)
+            ctx->Driver.FlushMappedBufferRange(ctx, target,
+                                               offset, length,
+                                               exec->vtx.bufferobj);
+      }
 
       exec->vtx.buffer_used += (exec->vtx.buffer_ptr -
                                 exec->vtx.buffer_map) * sizeof(float);