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

On Fri, Nov 07, 2008 at 11:40:21AM +0800, Zhao, Yu wrote:

Greg KH wrote:

quoted

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.

Can we use the suspend/resume code to do this?  Some drivers (sym2 for
one) would definitely need to rerun some of their init code to cope with
a BAR address changing.

-- 
Matthew Wilcox				Intel Open Source Technology Centre
"Bill, look, we understand that you're interested in selling us this
operating system, but compare it to ours.  We can't possibly take such
a retrograde step."