[PATCH v2 1/1] Split VGA default device handler out of VGA arbiter

On Sat, 2017-08-19 at 10:47 -0500, Bjorn Helgaas wrote:

So if ARM64 doesn't have these PCI legacy resources, does that mean an
ARM64 host bridge cannot generate these legacy addresses on PCI?  That
is, there's no host bridge window that maps to those PCI addresses?
That seems like a curious restriction on host bridges, but I guess it
would be possible.

It's rather common. For example on POWER8:

 - There is no IO space at all

 - We configure the 32-bit MMIO window to be around 3..4G (to avoid
overlapping with DMA space below it).

So we effectively have no path to the legacy areas, and that hasn't
been a problem so far.

Cheers,
Ben.