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=-0.8 required=3.0 tests=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 45E82C04ABB for ; Thu, 13 Sep 2018 12:17:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E63E920881 for ; Thu, 13 Sep 2018 12:17:52 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E63E920881 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727824AbeIMR1E (ORCPT ); Thu, 13 Sep 2018 13:27:04 -0400 Received: from mga01.intel.com ([192.55.52.88]:2689 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727051AbeIMR1D (ORCPT ); Thu, 13 Sep 2018 13:27:03 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by fmsmga101.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 13 Sep 2018 05:17:49 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.53,369,1531810800"; d="scan'208";a="85653642" Received: from ahunter-desktop.fi.intel.com (HELO [10.237.72.98]) ([10.237.72.98]) by fmsmga002.fm.intel.com with ESMTP; 13 Sep 2018 05:17:24 -0700 Subject: Re: [PATCH RFC] scsi: ufs: Disable blk-mq for now To: Ming Lei Cc: "Martin K . Petersen" , "James E . J . Bottomley" , Jens Axboe , Christoph Hellwig , Johannes Thumshirn , Bart Van Assche , linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org, Stanislav Nijnikov , Evan Green , Vinayak Holikatti , Janek Kotas , Vivek Gautam , Asutosh Das , Subhash Jadavani , Sayali Lokhande , Li Wei , Bjorn Andersson , Jaegeuk Kim , Alim Akhtar , Alex Lemberg References: <20180913112848.7807-1-adrian.hunter@intel.com> <20180913120459.GA4965@ming.t460p> From: Adrian Hunter Organization: Intel Finland Oy, Registered Address: PL 281, 00181 Helsinki, Business Identity Code: 0357606 - 4, Domiciled in Helsinki Message-ID: Date: Thu, 13 Sep 2018 15:15:39 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <20180913120459.GA4965@ming.t460p> Content-Type: text/plain; charset=utf-8 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 13/09/18 15:05, Ming Lei wrote: > On Thu, Sep 13, 2018 at 02:28:48PM +0300, Adrian Hunter wrote: >> blk-mq does not support runtime pm, so disable blk-mq support for now. > > So could you describe a bit what the issue you are trying to fix? UFS is a low-power solution, so we must be able to runtime suspend. > > This is host level runtime PM you are trying to address, and if blk-mq > runtime isn't enabled, I guess the host won't be runtime suspended at all > because some of its descendant are always active. > > So seems we need to do nothing for preventing the host controller from > entering runtime suspend. We don't want to prevent the host controller from runtime suspending, quite the opposite.