Re: [Patch v2] Make PCI extended config space (MMCONFIG) a driver opt-in

Benjamin Herrenschmidt
2007-12-28T06:08:17Z

On Thu, 2007-12-27 at 21:37 -0800, Linus Torvalds wrote:
>
> On Fri, 28 Dec 2007, Benjamin Herrenschmidt wrote:
> >
> > I have embedded boards where proper CRS operations is critical since the
> > kernel brings the PCIe link up itself, and thus is likely to hit devices
> > still in the middle of CRS.
>
> .. but that's perfectly fine. A PCI-E bridge will certainly retry it in
> hardware (or it isn't a PCI-E bridge!).

Only a handful of times in many bridges I've seen.

> So I'm going to disable that thing. If there is some _other_ PCI-E bridge
> that is simply buggy, and cannot handle the hw retry itself or is just
> otherwise dodgy, we can have a white-list for cases where it really needs
> to be done, but the current code is just bogus.

If you disable it, then isn't there also a problem with PCIE->PCI-X
bridge which will stop issuing CRS when they should ? (not sure here, I
may be a bit confused).

Ben.