cxgbe has odd m_margin
mac->m_margin = 22; /* TODO: mac_register(9s) and onnv code disagree */
m_margin value should be the number of bytes the device may present beyond the basic frame header. Given that cxgbe is an ethernet device driver, this should probably be
VLAN_TAGSZ like the rest of the ethernet drivers. However, it might be good to double check mac's usage of
mi_margin and make sure the man page has it right.