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=-7.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, 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 C1901C433FF for ; Mon, 29 Jul 2019 11:32:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9F974206B8 for ; Mon, 29 Jul 2019 11:32:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387714AbfG2Lcw (ORCPT ); Mon, 29 Jul 2019 07:32:52 -0400 Received: from foss.arm.com ([217.140.110.172]:42442 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387483AbfG2Lcw (ORCPT ); Mon, 29 Jul 2019 07:32:52 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 1661728; Mon, 29 Jul 2019 04:32:51 -0700 (PDT) Received: from e121166-lin.cambridge.arm.com (unknown [10.1.196.255]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 110E23F694; Mon, 29 Jul 2019 04:32:48 -0700 (PDT) Date: Mon, 29 Jul 2019 12:32:44 +0100 From: Lorenzo Pieralisi To: Geert Uytterhoeven Cc: Eugeniu Rosca , Ulrich Hecht , "horms@verge.net.au" , "khiem.nguyen.xt@renesas.com" , "dien.pham.ry@renesas.com" , "takeshi.kihara.df@renesas.com" , Kuninori Morimoto , "linux-renesas-soc@vger.kernel.org" , "Wischer, Timo (ADITG/ESM)" , "Maik.Scholz@de.bosch.com" , "Dirk.Behme@de.bosch.com" , Eugeniu Rosca , Daniel Lezcano , Linux PM list , Linux ARM Subject: Re: [PATCH v2 2/5] arm64: dts: r8a7795: Add cpuidle support for CA53 cores Message-ID: <20190729113244.GA12631@e121166-lin.cambridge.arm.com> References: <1547808474-19427-1-git-send-email-uli+renesas@fpond.eu> <1547808474-19427-3-git-send-email-uli+renesas@fpond.eu> <20190726091325.GA13111@vmlxhi-102.adit-jv.com> <20190726094724.GA14913@vmlxhi-102.adit-jv.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-renesas-soc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-renesas-soc@vger.kernel.org On Mon, Jul 29, 2019 at 09:44:52AM +0200, Geert Uytterhoeven wrote: > Hi Eugniu, > > CC cpuidle people > > On Fri, Jul 26, 2019 at 11:47 AM Eugeniu Rosca wrote: > > On Fri, Jul 26, 2019 at 11:13:29AM +0200, Rosca, Eugeniu (ADITG/ESM1) wrote: > > [..] > > > The culprit BSP commits are: > > > https://git.kernel.org/pub/scm/linux/kernel/git/horms/renesas-bsp.git/commit/?id=3c3b44c752c4ee > > > https://git.kernel.org/pub/scm/linux/kernel/git/horms/renesas-bsp.git/commit/?id=902ff7caa32dc71c > > > > > > Further narrowing it down, it turns out the CA57 cpuidle support is > > > not responsible for generating the issue. It's all about the CA53 idle > > > enablement. The reference target is H3-ES2.0-Salvator-X (the problem > > > originally emerged on M3-based customer HW). > > [..] > > > > Small amendment to the above (based on vanilla testing): > > > > Version Issue reproduced? > > (H3-ES2.0-Salvator-X) > > v5.3-rc1-96-g6789f873ed37 No > > v5.3-rc1-96-g6789f873ed37 + [1] No > > v5.3-rc1-96-g6789f873ed37 + [2] No > > v5.3-rc1-96-g6789f873ed37 + [1] + [2] Yes > > > > [1] https://patchwork.kernel.org/patch/10769701/ > > ("[v2,1/5] arm64: dts: r8a7795: Add cpuidle support for CA57 cores") > > > > [2] https://patchwork.kernel.org/patch/10769689/ > > ("[v2,2/5] arm64: dts: r8a7795: Add cpuidle support for CA53 cores") > > Thanks for your report and investigation! > > Unfortunately your original report didn't make it to lore.kernel.org, and > probably also not to the list, due to the large audio attachment. > > For the newly CCed people, the issue is about consistent dropouts > during audio playback using an in-house application, introduced by > adding cpuidle support to _both_ the big and LITTLE cores. CPUidle entry/exit latencies are certainly bringing the issue about, I am not an audio expert but I suspect buffering should be tuned to cope with those _increased_ latencies or possibly idle states disabled for certain specific use cases - there is no silver bullet, entering deep idle states will increase latencies, there is no way around it. I am happy to help you debug the issue further. Lorenzo