Hi Pawel, >From the code of this file, it seems the controller driver is running at PC side, but the hardware controller is at verification board, the two sides are connected by PCIe. Am I right? If I am right, the memory (eg, the TRB ring address and data buffer) the hardware try to visit is at PC side, but how controller visits PC memory since the TRB ring address is allocated dynamically by controller device driver running at PC? How the local bus arbiter knows it is PCIe address at verification board? Besides, could the upstream code run this IP verification solution through PCIe without changing any code? Thanks. -- Thanks, Peter Chen