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=-5.0 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 A178BC433E0 for ; Wed, 20 May 2020 19:07:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7F8A5206B6 for ; Wed, 20 May 2020 19:07:15 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=mg.codeaurora.org header.i=@mg.codeaurora.org header.b="KxJwpO1D" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726791AbgETTHP (ORCPT ); Wed, 20 May 2020 15:07:15 -0400 Received: from mail27.static.mailgun.info ([104.130.122.27]:44538 "EHLO mail27.static.mailgun.info" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726560AbgETTHO (ORCPT ); Wed, 20 May 2020 15:07:14 -0400 DKIM-Signature: a=rsa-sha256; v=1; c=relaxed/relaxed; d=mg.codeaurora.org; q=dns/txt; s=smtp; t=1590001634; h=Content-Transfer-Encoding: Content-Type: In-Reply-To: MIME-Version: Date: Message-ID: From: References: Cc: To: Subject: Sender; bh=QXlLEUKSHL/0UjZpVA1wNzA6wRLVED9Vpod9975E1rc=; b=KxJwpO1D/6bFRjz02lxK1VcHrNzERMs+J1KJoZ0MY1lGFcvEeEqcAMQT2XrlJOjLYmeP51mN zrQpiwe1sb7MLk2U922pxBc9OMh1ln0d/3CwoF/5/B+8E/Dv2Qmr8RJgSiyGjyOZOe3t+q/i gwh+PjGGYkJ0TM6i84EgSPrYsMQ= X-Mailgun-Sending-Ip: 104.130.122.27 X-Mailgun-Sid: WyI1MzIzYiIsICJsaW51eC1hcm0tbXNtQHZnZXIua2VybmVsLm9yZyIsICJiZTllNGEiXQ== Received: from smtp.codeaurora.org (ec2-35-166-182-171.us-west-2.compute.amazonaws.com [35.166.182.171]) by smtp-out-n02.prod.us-east-1.postgun.com with SMTP id 5ec57fcd62ee3a3497b55602 (version=TLS1.2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256); Wed, 20 May 2020 19:06:53 GMT Received: by smtp.codeaurora.org (Postfix, from userid 1001) id 1E5A5C433C9; Wed, 20 May 2020 19:06:53 +0000 (UTC) Received: from [10.226.58.28] (i-global254.qualcomm.com [199.106.103.254]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: jhugo) by smtp.codeaurora.org (Postfix) with ESMTPSA id 2A298C433C8; Wed, 20 May 2020 19:06:52 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 2A298C433C8 Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; spf=none smtp.mailfrom=jhugo@codeaurora.org Subject: Re: [PATCH v3 2/7] bus: mhi: core: Introduce independent voting mechanism To: bbhatt@codeaurora.org Cc: manivannan.sadhasivam@linaro.org, linux-arm-msm@vger.kernel.org, hemantk@codeaurora.org, linux-kernel@vger.kernel.org References: <1589832241-13867-1-git-send-email-bbhatt@codeaurora.org> <1589832241-13867-3-git-send-email-bbhatt@codeaurora.org> <574a4fe915f86608b59f10577eb960e9@codeaurora.org> From: Jeffrey Hugo Message-ID: Date: Wed, 20 May 2020 13:06:50 -0600 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.7.0 MIME-Version: 1.0 In-Reply-To: <574a4fe915f86608b59f10577eb960e9@codeaurora.org> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-arm-msm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org On 5/20/2020 12:43 PM, bbhatt@codeaurora.org wrote: > On 2020-05-20 09:54, Jeffrey Hugo wrote: >> On 5/18/2020 2:03 PM, Bhaumik Bhatt wrote: >>> Allow independent votes from clients such that they can choose to vote >>> for either the device or the bus or both. This helps in cases where the >>> device supports autonomous low power mode wherein it can move to M2 >>> state without the need to notify the host. Clients can also vote only to >>> keep the underlying bus active without having the device in M0 state to >>> support offload use cases. >>> >>> Signed-off-by: Bhaumik Bhatt >>> --- >> >> I wonder, why doesn't this fit with runtimePM? > Hi Jeff, > > Can you elaborate? > > In short, with this patch, MHI just wants to give controller the option to > choose the vote type so we can implement autonomous low power mode entries > on both host and device. So, you are attempting to manage the power mode of the device. The standard mechanism to do so in Linux is runtime pm. https://elixir.bootlin.com/linux/latest/source/Documentation/driver-api/pm/devices.rst I'm no runtime pm expert, but it feels like your whole voting mechanism, etc is just reimplemeting that. Reimplementing the wheel, when its been a standard thing that the majority of the kernel uses is not usually acceptable. IMO, you need some sort of justification why runtime pm is not applicable for you, because I'm willing to bet Mani/Greg are going to ask the same. -- Jeffrey Hugo Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project.