Messages in this thread | | | Date | Mon, 14 Jan 2008 08:01:50 -0800 | From | Arjan van de Ven <> | Subject | Re: [Patch v2] Make PCI extended config space (MMCONFIG) a driver opt-in |
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On Mon, 14 Jan 2008 10:23:14 -0500 Tony Camuso <tcamuso@redhat.com> wrote:
> Arjan van de Ven wrote: > > On Mon, 14 Jan 2008 08:01:01 -0500 > > Tony Camuso <tcamuso@redhat.com> wrote: > >> > >> If we're going to differentiate MMCONFIG from > >> some other access mechanism, it only needs to be done at the > >> Northbridge level. Devices are electrically ignorant of the > >> protocol used between CPU and Northbridge to get the Northbridge > >> to assert config cycles on the bus. > > > > Again this is about having systems that don't need extended config > > space not use it. At all. The only way to do that is have the > > drivers say they need it, and not use it otherwise. It has NOTHING > > to do with how things are wired up. It's pure a kernel level policy > > decision about whether to use extended config space AT ALL. > > > > The problem with compelling device drivers to determine the PCI > config mechanism is that it must be forced upon arches that > have no PCI configuration quirks or don't even use the same > PCI config mechanisms as x86.
it's not pci_enable_mmconf(), it's pci_enable_extended_config_space... it's independent of the mechanism!
> > I don't think that's a good policy. > > Better to confine arch-specific quirks to the arch-specific code > whenever possible. >
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