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=-8.6 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable 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 6771DC433DF for ; Mon, 20 Jul 2020 08:06:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 47FF120702 for ; Mon, 20 Jul 2020 08:06:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1595232367; bh=DBU10xCfPXi9S7q1y4HELT5+p2XXLy5mMLrB0UTptkw=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=VgTxsV9PhR0mUb0lEdSLv3HVLX5QN3ofShSjjvTIhl4I2DG7ayurNUtyQo4eLHBKV 2Wvet62I2uaGXpxBs0fNg81GD6lovJ604U4m0CwPRz8DFIgv8mREU8jyCULOSITjOF sMMKXktdHJhEpBltKjm+dgr7GL41OwKd9YY5RYN0= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726030AbgGTIGG (ORCPT ); Mon, 20 Jul 2020 04:06:06 -0400 Received: from mail-wm1-f66.google.com ([209.85.128.66]:37069 "EHLO mail-wm1-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725815AbgGTIGG (ORCPT ); Mon, 20 Jul 2020 04:06:06 -0400 Received: by mail-wm1-f66.google.com with SMTP id o2so24236749wmh.2; Mon, 20 Jul 2020 01:06:04 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=vg09xK5q93RhjkSo+BtXD7JwKBjiF9ZCt45w+OmMMVY=; b=fUTMldOGfkrptj+n6jUNqqziKMMf/cgU3ebuM7YHLJZ0XgOOJqWml/zNAXU9MZAt1a mGZvgYzT/+3kYDfQLwSwmS+97D3X71N0LmiMg3B5PnXTfT/0q4jEw+ErAXYjQu39erMv PbSgzLHrqupo1/SbayKs7x3vx2lM2nE46s3LgQ2TmVm+ZkJXuxqz7NI3BWncEoacBi4W 3tC4eBog3hxZ4MDad6D6MPar6pq5JdCYA3wpVYVNh5IRU/TZf7xK3PDgIHBjkIQX+I5R 8xh6BibHYZ5Pd+acRH32bmKIZlUob72pbi5dVB2V9g6pE1J188m3hqVTBDOtLLNTNlyR jLsw== X-Gm-Message-State: AOAM531qDr6XfPxZ57hpenTGrvUIwQWgLD3OZ9TpTfXB+rzzmUYaao2z dP8m+sbw2MRjojiVe49Jaz++uIB7z3g= X-Google-Smtp-Source: ABdhPJxJ8ZIsf7AKkJqYCmB3NDTY1+PGtOCnwv5Wvo5iWqmnU/v7hbUEipw+IMyAcld5Qa3frDje4g== X-Received: by 2002:a7b:c3d0:: with SMTP id t16mr21900753wmj.117.1595232364225; Mon, 20 Jul 2020 01:06:04 -0700 (PDT) Received: from kozik-lap ([194.230.155.200]) by smtp.googlemail.com with ESMTPSA id l67sm34178337wml.13.2020.07.20.01.06.02 (version=TLS1_2 cipher=ECDHE-ECDSA-CHACHA20-POLY1305 bits=256/256); Mon, 20 Jul 2020 01:06:03 -0700 (PDT) Date: Mon, 20 Jul 2020 10:06:01 +0200 From: Krzysztof Kozlowski To: Marek Szyprowski Cc: linux-samsung-soc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org, Bartlomiej Zolnierkiewicz , Willy Wolff , Marian Mihailescu , Chanwoo Choi Subject: Re: [PATCH] ARM: dts: exynos: Disable frequency scaling for FSYS bus Message-ID: <20200720080601.GA3845@kozik-lap> References: <20200714064759.31772-1-m.szyprowski@samsung.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20200714064759.31772-1-m.szyprowski@samsung.com> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org On Tue, Jul 14, 2020 at 08:47:59AM +0200, Marek Szyprowski wrote: > Commit 1019fe2c7280 ("ARM: dts: exynos: Adjust bus related OPPs to the > values correct for Exynos5422 Odroids") changed the parameters of the > OPPs for the FSYS bus. Besides the frequency adjustments, it also removed > the 'shared-opp' property from the OPP table used for FSYS_APB and FSYS > busses. > > This revealed that in fact the FSYS bus frequency scaling never worked. > When one OPP table is marked as 'opp-shared', only the first bus which > selects the OPP sets the rate of its clock. Then OPP core assumes that > the other busses have been changed to that OPP and no change to their > clock rates are needed. Thus when FSYS_APB bus, which was registered > first, set the rate for its clock, the OPP core did not change the FSYS > bus clock later. > > The mentioned commit removed that behavior, what introduced a regression > on some OdroidXU3 boards. Frequency scaling of the FSYS bus causes > instability of the USB host operation, what can be observed as network > hangs. To restore old behavior, simply disable frequency scaling for the > FSYS bus. > > Reported-by: Willy Wolff > Fixes: 1019fe2c7280 ("ARM: dts: exynos: Adjust bus related OPPs to the values correct for Exynos5422 Odroids") > Signed-off-by: Marek Szyprowski > --- > arch/arm/boot/dts/exynos5422-odroid-core.dtsi | 6 ------ > 1 file changed, 6 deletions(-) Thanks Willy and Marek for digging into this, applied. A follow up question would be if other boards (Exynos4412) require the same? Best regards, Krzysztof