From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jaehoon Chung Subject: Re: [PATCHv10 0/5] ARM: remove the sub-node and deprecate supports-highspeed property for dwmmc. Date: Wed, 27 Aug 2014 12:11:55 +0900 Message-ID: <53FD4C7B.2030008@samsung.com> 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> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: In-reply-to: <20140826101923.GA13619@amd> Sender: linux-samsung-soc-owner@vger.kernel.org To: Pavel Machek , 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 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.. https://patchwork.kernel.org/patch/4276481/ Best Regards, Jaehoon Chung > > Pavel >