Musings on PCI busses

[David Miller]

From: Benjamin Herrenschmidt <benh at kernel.crashing.org>
Date: Wed, 20 May 2009 13:01:30 +1000

> For example, some of the OF parsing bits may fail to convert memory
> addresses to IO addresses if the PCI host bridges have not been
> discovered yet, potentially causing issues with matching of resources
> between the early serial stuff and the generic serial driver (if you
> use an IO driven UART, the PCI 8250 driver may not properly figure out
> that what it's finding in its IO BARs is actually the same port as
> what it gets from the platform code as the later will end up with
> memory addresses rather than IO ones). That's one example.

FWIW, I never run into this issue on sparc64 exactly because I
fully resolve all resources when I populate the OF device tree
in the kernel.