How to check the PXIe port is running GEN2 or GEN3?

Guide to PCIe Lanes: How many do you need for your workload? pcie slot configuration gen1 gen2 gen3 PCIe supports PCIe Gen 1, PCIe Gen 2, and PCIe Gen 3 devices PCIe With options for 1x, 2x, 4x, 8x, and 16x slot configurations pcie training error slot 1 where as this gen 1 and gen 2 is only for troubled slot not able to run gen-3 and needs to be down grade to gen 1 or 2? may be I should go home

pcie 8x slot Socket Configuration ->VMD config for PStackN PCIE Slot Location Auto Gen1 Gen2 Gen3 Max Payload Size PCIE Max Payload Size Selection