Why does my Hard IP for PCI Express in Root Port mode not return a Vendor ID=0xFFFFFFFF for a device that's not present? - Why does my Hard IP for PCI Express in Root Port mode not return a Vendor ID=0xFFFFFFFF for a device that's not present? Description This behavior is expected. If a configuration read is attempted for a device that is not present on a downstream bus (or for busses not present), the Hard IP core will return a Completion without data, showing Unsupported Request (UR). Resolution The driver software communicating with the Hard IP core must be aware that a configuration read of the Vendor ID register was pending and that the Completion without data and UR indicate device/bus/function not present. If this request was from higher layer software the driver should report a Vendor ID=0xFFFFFFFF to meet the expectations of system software components. The Altera® Hard IP for PCI® Express is a root port device, it is the surrounding Root Complex that is responsible for reporting the 0xFFFFFFFF Vendor ID. Custom Fields values: ['novalue'] Troubleshooting novalue False ['novalue'] ['novalue'] novalue novalue ['Arria® V GT FPGA', 'Arria® V GX FPGA', 'Arria® V GZ FPGA', 'Arria® V ST FPGA', 'Arria® V SX FPGA', 'Cyclone® V GT FPGA', 'Cyclone® V GX FPGA', 'Cyclone® V SE FPGA', 'Cyclone® V ST FPGA', 'Cyclone® V SX FPGA', 'Arria® 10 GT FPGA', 'Arria® 10 GX FPGA', 'Arria® 10 SX FPGA', 'Stratix® V E FPGA', 'Stratix® V GS FPGA', 'Stratix® V GT FPGA', 'Stratix® V GX FPGA'] ['novalue'] ['novalue'] ['novalue']