What is the purpose of the cfg_dsn port? What should the cfg_dsn port be driven to if not using this capability Can I disable this capability?
Section 7.12 of the PCI Express Base Specification v1.1 defines the Device Serial Number capability. This is an optional PCI Express extended capability, however, the Xilinx PCIe Block Plus v1.2 and Xilinx PCIe v3.4 soft core solutions automatically implement this capability when the core is generated. This field contains the IEEE defined 64-bit extended unique identifier (EUI-64). The EUI-64 is formed by concatenating the 24-bit OUI (Organizationally Unique Identifier) obtained from IEEE along with a 40-bit extension identifier that is assigned by the company to uniquely identify the device.
You should drive this port with your own OUI; this information can be found at:
Currently, the Xilinx endpoint core does not allow you to disable this capability. An enhancement request has been filed to make this feature an option in the GUI. In a future release, you will have the option to turn this capability Off when generating the core. Until then, if you do not have you own OUI or cannot purchase one, leave the default value (which is the Xilinx OUI).