Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755527AbYLKBo3 (ORCPT ); Wed, 10 Dec 2008 20:44:29 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753023AbYLKBoS (ORCPT ); Wed, 10 Dec 2008 20:44:18 -0500 Received: from mga09.intel.com ([134.134.136.24]:47077 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752451AbYLKBoR (ORCPT ); Wed, 10 Dec 2008 20:44:17 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.33,749,1220252400"; d="scan'208";a="472952610" Date: Thu, 11 Dec 2008 09:43:13 +0800 From: Yu Zhao To: Matthew Wilcox Cc: Greg KH , "linux-pci@vger.kernel.org" , "achiang@hp.com" , "grundler@parisc-linux.org" , "mingo@elte.hu" , "jbarnes@virtuousgeek.org" , "randy.dunlap@oracle.com" , "rdreier@cisco.com" , "linux-kernel@vger.kernel.org" , "kvm@vger.kernel.org" , "virtualization@lists.linux-foundation.org" Subject: Re: [PATCH 16/16 v6] PCI: document the new PCI boot parameters Message-ID: <20081211014313.GA4947@yzhao12-linux.sh.intel.com> References: <20081022083809.GA3757@yzhao12-linux.sh.intel.com> <20081022084531.GP3773@yzhao12-linux.sh.intel.com> <20081106043235.GA30292@kroah.com> <4913AA03.5060807@intel.com> <20081107025032.GA12824@kroah.com> <4913B8A5.5010806@intel.com> <20081107041721.GB15439@parisc-linux.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20081107041721.GB15439@parisc-linux.org> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1927 Lines: 43 On Fri, Nov 07, 2008 at 12:17:22PM +0800, Matthew Wilcox wrote: > On Fri, Nov 07, 2008 at 11:40:21AM +0800, Zhao, Yu wrote: > > Greg KH wrote: > > >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. Yes, that is what I was thinking. But after some grep on the PCI device drivers, I feel frustrated because all those drivers only do 'ioremap' once at the 'probe' stage. I believe this is the only problem that preclude us having the run-time resource rebalance. And I'm not sure how much effort we can fix it. Any comments? Thanks, Yu -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/