Subject: Re: Problem with PCI bus rescan on 460EX

From: Benjamin Herrenschmidt <[email-masked]>
Date: Mon, 15 Mar 2010 16:46:46 +1100

On Mon, 2010-03-15 at 14:39 +0900, Kenji Kaneshige wrote:
> 
> > Yes, with these lines removed bridge memory window is properly
> allocated.
> 
> These lines are to prevent updating IO or memory windows when there
> are
> some devices working behind the bridge. So please note that removing
> these lines is just for debugging.

This is not a very good way to do so though. Many firmwares will leave
those enabled even when the bridges -do- have to be reconfigured.

Worse... the code means that the kernel -will- have updated its resource
tree, probably assigned new resources, etc... to those bridges, and thus
to devices underneath them, but will silently fail to actually update
the bridge BARs to match.

This seems like a major bug to me in fact.

Cheers,
Ben.