X710/XL710/XXV710 NICs lack support for indicating INTx is asserted via the
interrupt bit in the PCI status register. Linux deleted them from INTx support
table. The related commit.

Implication:
When insmod igb_uio with intr_mode=legacy and test link status interrupt. Since
INTx interrupt is not supported by X710/XL710/XXV710, it will cause
Input/Output error when reading file descriptor.

Resolution/Workaround:
Do not bind igb_uio with legacy mode in X710/XL710/XXV710 NICs, or do not use
kernel version >4.7 when you bind igb_uio with legacy mode.

Affected Environment/Platform:
ALL.

Driver/Module:
Poll Mode Driver (PMD).