   D3D10: STAGING Buffer
  Hello,just a little question about a D3D10 STAGING Vertexbuffer. Does Map() on a STAGING buffer immediately return? vb->Map(D3D10_MAP_READ_WRITE, 0, reinterpret_cast<void**>(&heightData));Is this call fast? Or could this call produce a stall?   
  I believe that a staging resource is resident in main memory.  Evidence of this is that you cannot bind a staging resource to the pipeline.  When you copy data to it, for instance when using the CopyResoure() API, the driver most likely begins a data transfer from the GPU to the CPU.  The Map call may force a flush if the system determines that there are outstanding commands waiting for access to that resource.  If there are no such commands, and the data transfer has completed, then the call to Map probably will not block.This page may be of some use in determining the restrictions of resource types.   