Heh. That's how PCI sizing works: you write all ones to the register, and
read back the result. The low bits won't change, and that indicates the
But if _none_ of the bits change, then that simply means that the size
will be calculated to be 0xffffffff-start.
So the sizing will "work", it will just always report that the BAR covers
everything from start to the 4G limit.