From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from gate.crashing.org (gate.crashing.org [63.228.1.57]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTP id 3C852DDDFF for ; Sun, 14 Jan 2007 07:40:19 +1100 (EST) Subject: Re: [PATCH 2/7] Powerpc MSI implementation From: Benjamin Herrenschmidt To: Greg KH In-Reply-To: <20070113192734.GA30867@kroah.com> References: <1168514716.63474.857278133999.qpush@cradle> <20070111112503.0CC1BDDF13@ozlabs.org> <20070111194427.GA20450@kroah.com> <1168550403.22458.414.camel@localhost.localdomain> <1168552498.22458.428.camel@localhost.localdomain> <20070112231317.GC665@kroah.com> <1168667863.5011.44.camel@localhost.localdomain> <20070113192734.GA30867@kroah.com> Content-Type: text/plain Date: Sun, 14 Jan 2007 07:40:15 +1100 Message-Id: <1168720815.5011.70.camel@localhost.localdomain> Mime-Version: 1.0 Cc: linuxppc-dev@ozlabs.org, Paul Mackerras , Olof Johannsson , linux-pci@atrey.karlin.mff.cuni.cz List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , > I'm saying I don't want to see 2 different MSI implementations in the > kernel. I'm sure you can understand this reasoning. > > I misunderstood your original patches in that I thought you were > cleaning up the generic versions for everyone, not creating a separate > set of APIs. Sorry for the misunderstanding. It's not a separate set of APIs. The APIs are the same (as far as drivers are concerned). We are providing a new "core" that indeed aims are replacing the current one (and provides the same APIs to drivers). We have two backends implemented for it for now, soon 3 as I need to write one for Cell blades. So at this point we have three possible approaches: 1- We can put it entirely in arch/powerpc. You NAKed the few generic changes to pci.h but we can hide that in sysdata or some other ppc specific stuff hanging off pci_dev. That is maybe the easiest approach for us to at least have MSI support in 2.6.21. (We really do need MSI support in urgently). 2- We can put it as I suggested and you just NAKed in drivers/pci/msi-new.c along with our new backends. Thus, Kconfig defines wether the old core is used (Intel,Altix) or the new core. I still feel that's the best option as it makes it easier for other archs (including Intel & Altix) to port MSI support to the new infrastructure as it will be there. Maybe the best approach is to compromise here and do that, but keep it in -mm until Intel and Altix are ported over in which case it can be merged in linus tree. 3- We can keep it out of tree and try to work with others to have Intel and Altix stuff ported over out of tree, until we have a new patch which completely replaces the existing stuff. I still think it's better to have the new core in -mm before everything is ported to it though. Ben.