From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pavel Machek Subject: Re: [PATCHv10 0/5] ARM: remove the sub-node and deprecate supports-highspeed property for dwmmc. Date: Wed, 27 Aug 2014 13:56:31 +0200 Message-ID: <20140827115631.GA2536@amd> References: <1407397082-32495-1-git-send-email-jh80.chung@samsung.com> <20140825112151.GA21336@amd> <53FB1DD5.3050207@samsung.com> <20140825113719.GA31960@amd> <53FB278B.7010509@samsung.com> <53FB2807.7070503@samsung.com> <20140826101923.GA13619@amd> <53FD4C7B.2030008@samsung.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <53FD4C7B.2030008@samsung.com> Sender: linux-mmc-owner@vger.kernel.org To: Jaehoon Chung Cc: Mark Rutland , devicetree@vger.kernel.org, Ulf Hansson , kgene.kim@samsung.com, heiko@sntech.de, tgih.jun@samsung.com, linux-mmc , Chris Ball , linux-samsung-soc@vger.kernel.org, dinguyen@altera.com, linux-arm-kernel@lists.infradead.org List-Id: devicetree@vger.kernel.org On Wed 2014-08-27 12:11:55, Jaehoon Chung wrote: > Hi, > > On 08/26/2014 07:19 PM, Pavel Machek wrote: > > Hi! > > > >>>> Would you elaborate? > >>>> > >>>> If I have a device like a phone, I may want to put one "slot" inside > >>>> phone for basic system, and offer second slot for user expansion > >>>> (initially empty). > >>> > >>> if multiple slot is supported, then a mmcqd should be processing for multiple slots. > >>> It's too inefficient, and affect the whole performance reduction. > >> Sorry, Discard this comment. it means dwmci, not mmcqd. > > > > Well, that's a Linux problem, and for many applications, not even > > problem at all. > > > > Device tree should describe hardware, and hardware can do multiple > > slots per controller, so device tree should describe multiple slots > > per controller. > > > > Now, the configuration may be uncommon, but you are moving from good > > hardware description to bad hardware description. > > Well, i don't think it's bad hardware description. And this policy is suggested by other mmc developers and maintainers. > At first time, I had also suggested same opinion with yours. > Refer to below.. Well, I disagree with them. They want to modify device tree because of linux limitations. Plus. I guess that sooner or later someone will wire just the slot 1 (not 0) and not match this description. Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html