Re: [PATCH 16/16 v6] PCI: document the new PCI boot parameters

From: Pavel Machek
Date: Sun Nov 09 2008 - 09:19:34 EST


Hi!

> >>> If we do resource rebalance after system is up, do you think there is any
> >>> side effect or impact to other subsystem other than PCI (e.g. MTRR)?
> >> I don't think so.
> >>> I haven't had much thinking on the dynamical resource rebalance. If you
> >>> have any idea about this, can you please suggest?
> >> Yeah, it's going to be hard :)
> >> We've thought about this in the past, and even Microsoft said it was
> >> going to happen for Vista, but they realized in the end, like we did a
> >> few years previously, that it would require full support of all PCI
> >> drivers as well (if you rebalance stuff that is already bound to a
> >> driver.) So they dropped it.
> >> When would you want to do this kind of rebalancing? Before any PCI
> >> driver is bound to any devices? Or afterwards?
> >
> > I guess if we want the rebalance dynamic, then we should have it full --
> > the rebalance would be functional even after the driver is loaded.
> >
> > But in most cases, there will be problem when we unload driver from a hard
> > disk controller, etc. We can mount root on a ramdisk and do the rebalance
> > there, but it's complicated for a real user.
> >
> > So looks like doing rebalancing before any driver is bound to any device is
> > also a nice idea, if user can get a shell to do rebalance before built-in
> > PCI driver grabs device.
>
> That's not going to work, it needs to happen before any PCI device is
> bound, which is before init runs.

We could run shell from early initrd... And PCI is not required for
initrd, right?

(Ok, I guess this is in we could do it but is it worth the cost?-category...)

--
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