From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-1.0 required=3.0 tests=FREEMAIL_FORGED_FROMDOMAIN, FREEMAIL_FROM,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A0423C282C2 for ; Wed, 13 Feb 2019 10:06:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6F6562147C for ; Wed, 13 Feb 2019 10:06:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387998AbfBMKGV (ORCPT ); Wed, 13 Feb 2019 05:06:21 -0500 Received: from smtp3-g21.free.fr ([212.27.42.3]:42805 "EHLO smtp3-g21.free.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727580AbfBMKGV (ORCPT ); Wed, 13 Feb 2019 05:06:21 -0500 Received: from [192.168.108.68] (unknown [213.36.7.13]) (Authenticated sender: marc.w.gonzalez) by smtp3-g21.free.fr (Postfix) with ESMTPSA id 9169513F8F1; Wed, 13 Feb 2019 11:05:28 +0100 (CET) Subject: Re: [PATCH v5 1/2] scsi: ufs: Do not disable vccq in UFSHC driver To: Mark Brown Cc: SCSI , LKML , Jeffrey Hugo , Bjorn Andersson , Evan Green , Douglas Anderson , Alim Akhtar , Avri Altman , Pedro Sousa , Joao Pinto , Liam Girdwood , Rob Herring , Bart Van Assche , Stanislav Nijnikov , Alex Lemberg , Ohad Sharabi , Venkat Gopalakrishnan , Subhash Jadavani , Yaniv Gardi , Raviv Shvili , Hannes Reinecke , Kyuho Choi , Martin Petersen References: <494cd639-89a7-8868-b63a-ea7cdcba9777@free.fr> <20190211172340.GG22391@sirena.org.uk> From: Marc Gonzalez Message-ID: Date: Wed, 13 Feb 2019 11:05:28 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.4.0 MIME-Version: 1.0 In-Reply-To: <20190211172340.GG22391@sirena.org.uk> Content-Type: text/plain; charset=windows-1252 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/02/2019 18:23, Mark Brown wrote: > On Mon, Feb 11, 2019 at 02:32:15PM +0100, Marc Gonzalez wrote: > >> Unfortunately, this optimization breaks UFS on systems where vccq >> powers not only the Flash chip, but the host controller as well, >> such as APQ8098 MEDIABOX or MTP8998. >> >> In my opinion, the rationale for the original patch is questionable. >> If neither the UFSHC, nor the Flash chip, require any load from vccq, >> then that power rail should simply not be specified at all in the DT. > > If the supply is physically connected it should be valid to represent > this in DT regardless of how or if the supply gets used at runtime. > However it does sound like this support needs to be better thought > through to make sure we have represented the supplies to the flash chip > and the controller separately - it seems like right now there's no > tracking of the supplies needed for the controller and the assumption is > that only the flash chip needs managing which is breaking things. As far as I'm aware, the conflation of host controller with their respective storage medium occurs across several techs: UFS, NAND, SDHC, EMMC. There might be room for improvement, but I don't think these considerations should hold up this series, which fixes something that is broken *today*. UFS reviewers (Alim, Avri, Pedro), can I get at least one Acked-by to remove this small power optimization that breaks UFS on my system? Regards.