From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1763472AbYHEVhs (ORCPT ); Tue, 5 Aug 2008 17:37:48 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756071AbYHEVhk (ORCPT ); Tue, 5 Aug 2008 17:37:40 -0400 Received: from smtp1.linux-foundation.org ([140.211.169.13]:46169 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754279AbYHEVhk (ORCPT ); Tue, 5 Aug 2008 17:37:40 -0400 Date: Tue, 5 Aug 2008 14:37:19 -0700 (PDT) From: Linus Torvalds To: Sean MacLennan cc: Karsten Keil , Benjamin Herrenschmidt , "Andreas.Eversberg" , isdn4linux@listserv.isdn4linux.de, linux-kernel@vger.kernel.org Subject: Re: [PATCH 3/4] Fix remaining big endian issue of hfcmulti In-Reply-To: <20080805172324.45853d98@lappy.seanm.ca> Message-ID: References: <20080802151532.DE017A3C09@pingi.kke.suse.de> <1217910588.24157.151.camel@pasglop> <20080805113111.GA6827@pingi.kke.suse.de> <1217941466.24157.190.camel@pasglop> <20080805172549.GA6052@pingi.kke.suse.de> <20080805210239.GB6052@pingi.kke.suse.de> <20080805172324.45853d98@lappy.seanm.ca> User-Agent: Alpine 1.10 (LFD 962 2008-03-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 5 Aug 2008, Sean MacLennan wrote: > > Why not select PIO or MMIO at config time? Umm. Then you can't run a generic driver that can do either. That's the worst choice of all. As to where in the stack to do the choice - I suspect it's easier if it's done at the lowest level, but that can cause performance issues (ie testing that flag over and over again). The mmio code avoids some of the performance issues exactly by doing the "repeat" versions - so for some cases you can do the check once at the top, and then just repeat. Linus