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=-0.6 required=3.0 tests=DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,T_DKIM_INVALID,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by aws-us-west-2-korg-lkml-1.web.codeaurora.org (Postfix) with ESMTP id 434E1C433EF for ; Thu, 14 Jun 2018 06:36:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E30A2208D4 for ; Thu, 14 Jun 2018 06:36:04 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="key not found in DNS" (0-bit key) header.d=codeaurora.org header.i=@codeaurora.org header.b="ZEjBuAMq"; dkim=fail reason="key not found in DNS" (0-bit key) header.d=codeaurora.org header.i=@codeaurora.org header.b="EvUv+m/E" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E30A2208D4 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=codeaurora.org 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 S1754634AbeFNGgC (ORCPT ); Thu, 14 Jun 2018 02:36:02 -0400 Received: from smtp.codeaurora.org ([198.145.29.96]:56038 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752925AbeFNGgB (ORCPT ); Thu, 14 Jun 2018 02:36:01 -0400 Received: by smtp.codeaurora.org (Postfix, from userid 1000) id A06E960792; Thu, 14 Jun 2018 06:36:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1528958160; bh=FfZ9Ycnt2ejE0fiGE+4iCLH3jVV0zg1LABJhuxxq1uI=; h=Subject:To:Cc:References:From:Date:In-Reply-To:From; b=ZEjBuAMqYe2viLvikw/GbXpY6VwywjsrqWoZNwHW1iq/CyxmbN12VPmQdBr91n6T9 HX1Zssk7Tpcy/yffdOGu7ICzCdnf0mpqmXzxmwBYuobY2VD2NXcbhH7r2dCR91T1iN BNrRZpGwGS+9RJyBTrazmQTr+CfgK1SibZo35Eoo= Received: from [10.79.40.88] (blr-bdr-fw-01_globalnat_allzones-outside.qualcomm.com [103.229.18.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: rnayak@smtp.codeaurora.org) by smtp.codeaurora.org (Postfix) with ESMTPSA id 89C8D60116; Thu, 14 Jun 2018 06:35:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1528958159; bh=FfZ9Ycnt2ejE0fiGE+4iCLH3jVV0zg1LABJhuxxq1uI=; h=Subject:To:Cc:References:From:Date:In-Reply-To:From; b=EvUv+m/EVvjzZPtj5mrM9jWA/jFKZGDBBdl1wlDXtyXnmDOe05tH8a31kll8fBsl0 1+h5rgOscXrgFz7WMNhvcRv4CcsthqT9o+8tRu/cRhCdQ4fo3IMOZa67CoCskzHnz0 Co5UrIll7FXl5srW9FzrwYRZpEU25zHNpJ8OhGLc= DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 89C8D60116 Authentication-Results: pdx-caf-mail.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: pdx-caf-mail.web.codeaurora.org; spf=none smtp.mailfrom=rnayak@codeaurora.org Subject: Re: [PATCH v3 7/7] soc: qcom: rpmpd/rpmhpd: Add a max vote on all corners at init To: David Collins , viresh.kumar@linaro.org, sboyd@kernel.org, andy.gross@linaro.org, ulf.hansson@linaro.org Cc: devicetree@vger.kernel.org, linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org References: <20180612044052.4402-1-rnayak@codeaurora.org> <20180612044052.4402-8-rnayak@codeaurora.org> <414598de-00a1-9ce7-3a7e-4a95fd1bd35d@codeaurora.org> From: Rajendra Nayak Message-ID: Date: Thu, 14 Jun 2018 12:05:55 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.7.0 MIME-Version: 1.0 In-Reply-To: <414598de-00a1-9ce7-3a7e-4a95fd1bd35d@codeaurora.org> 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 06/14/2018 03:58 AM, David Collins wrote: > Hello Rajendra, > > On 06/11/2018 09:40 PM, Rajendra Nayak wrote: >> As we move from no clients/consumers in kernel voting on corners, >> to *some* voting and some not voting, we might end up in a situation >> where the clients which remove votes can adversly impact others > > s/adversly/adversely/ > >> who still don't have a way to vote. >> >> To avoid this situation, have a max vote on all corners at init. >> This should/can be removed once we have all clients moved to >> be able to vote/unvote for themselves. > > This change seems like a hack. Do you intend for it to be merged and then > later reverted in Linus's tree? Could it instead be implemented in a way > that does not require reverting and instead is enabled by some DT > property? Alternatively, could this feature be added to the power domain > core since it is relatively generic? > > >> Signed-off-by: Rajendra Nayak >> Acked-by: Viresh Kumar >> --- >> drivers/soc/qcom/rpmhpd.c | 12 +++++++++++- >> drivers/soc/qcom/rpmpd.c | 9 +++++++++ >> 2 files changed, 20 insertions(+), 1 deletion(-) >> >> diff --git a/drivers/soc/qcom/rpmhpd.c b/drivers/soc/qcom/rpmhpd.c >> index 7083ec1590ff..3c753d33aeee 100644 >> --- a/drivers/soc/qcom/rpmhpd.c >> +++ b/drivers/soc/qcom/rpmhpd.c >> @@ -329,7 +329,7 @@ static int rpmhpd_update_level_mapping(struct rpmhpd *rpmhpd) >> >> static int rpmhpd_probe(struct platform_device *pdev) >> { >> - int i, ret; >> + int i, ret, max_level; >> size_t num; >> struct genpd_onecell_data *data; >> struct rpmhpd **rpmhpds; >> @@ -390,6 +390,16 @@ static int rpmhpd_probe(struct platform_device *pdev) >> pm_genpd_init(&rpmhpds[i]->pd, NULL, true); >> >> data->domains[i] = &rpmhpds[i]->pd; >> + >> + /* >> + * Until we have all consumers voting on corners >> + * just vote the max corner on all PDs >> + * This should ideally be *removed* once we have >> + * all (most) consumers being able to vote >> + */ >> + max_level = rpmhpds[i]->level_count - 1; >> + rpmhpd_set_performance(&rpmhpds[i]->pd, rpmhpds[i]->level[max_level]); >> + rpmhpd_power_on(&rpmhpds[i]->pd); > > Clearly these calls will result in max level requests being sent for all > power domains at probe time. However, it isn't clear that this will > actually help at runtime in these two cases: > > 1. A consumer enables and then disables a power domain. > - It seems like the PD would just be disabled in this case. > > 2. A consumer sets a non-max performance state of a power domain. > - It seems like the PD would just be set to the new lower > performance state since the max vote isn't known to the > PD core for aggregation purposes. Yes, you are right. I certainly did not seem to have thought through this enough. A need for something like this came up at a point where genpd could not deal with devices with multiple power domains. So the concern at that point was that if some consumers (which only need to vote on one corner) move to using this driver, while some others (which need to vote on multiple corners) cannot, we would end up breaking them. That does not seem to be true anymore since we do have patches from Ulf which support having devices with multiple power domains attached which can be controlled individually. So if some consumer voting makes some others break, they should just be fixed and patched to vote as well. If all this gets handled centrally from within the clock drivers then we most likely won't even end up with a situation like this. I think I will just drop this one unless Stephen/Viresh still see an issue with some early voters breaking others. -- Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation