Hello! In my company we developing custom network adapter and we have ASIC based PCIe card that works fine on various server systems (with AMD and Intel processors). But we have trouble with new AMD EPYC 7351 supermicro server (h11dsi-nt motherboard). Device is succesfully initialized by system and we can see it in lspci log:
However, when we trying to read device specific registers from BAR2 it returns 0xFFFFFFF:
Usually that means that request was completed by timeout. But why this happening? On other systems this works fine... What steps do we need to perform to debug this issue?