Hi Wesley, It looks like I can get the transfer ring address by calling xhci_get_xfer_resource, and the xhci_get_ir_resource() is called to get access to the new structure "xhci_interrupter" for the event ring address. From code review, I can say these APIs allow us to get the information we need. Of course, we will integrate this patchset to verify if compatible with our design. Thanks, Albert