d4ed36cde2
According to the PCI Local Specification rev. 3.0 in case of a 64-bit BAR both the low and the high parts of the register should be set to ~0 before attempting to read back the size. So far I have found no single device that has problems with the previous approach, but I think it's better to stay on the safe size. This commit should not introduce any functional change. MFC after: 3 weeks Sponsored by: Citrix Systems R&D Reviewed by: jhb Differential revision: https://reviews.freebsd.org/D11750