On Thu, Jan 09, 2003 at 03:35:32PM -0800, Linus Torvalds wrote:
> The only real reason to worry about BAR sizing is really to do resource
> discovery in order to make sure that out bridges have sufficiently big
> windows for the IO regions. Agreed?
yes. And eventually to make sure regions don't overlap.
> And that should be a non-issue especially on a host bridge, since we
> almost certainly don't want to reprogram the bridge windows there anyway.
Current PARISC servers do not allocate MMIO/IO resources for all PCI devices.
Only boot devices are configured. Fortunately, default MMIO/IO address
space assigned to Host bridges seems to work - at least I've not heard
anyone complain (yet). But no one has tried PCI expansion chassis or
cards with massive (> 64MB) MMIO BARs.
Because of PCI hotplug, rumor is ia64 firmware folks want to do
the same thing in the near future.
> So I'd like to make the _default_ be to probe the minimal possible,
> _especially_ for host bridges. Then, the PCI quirks could be used to
> expand on that default.
That's reasonable.
pci arch code also has hooks to fixup host bridge resources.
thanks,
grant
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
This archive was generated by hypermail 2b29 : Wed Jan 15 2003 - 22:00:30 EST