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 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id C95D7D767CB for ; Fri, 19 Dec 2025 10:42:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To: Content-Transfer-Encoding:Content-Type:MIME-Version:References:Message-ID: Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=+Rr6AOIc4U8eWnOIbWXPg2cTyBi21t7kJJ99fYA2XhQ=; b=SMN2sfkN4humN06wVqlg8znIxv +3ntGoHieTcL4aLc0LC16+lRkdnbkxgSZFqKNpoavobXhkarCw6kMuW7mAeOI+0A/RCC7UJTAPQlh a8OLRHHth21c1zRLn8RKJoXqg1FOmFNBbCnYDRHOiMyWjcXnuxc/Mvq+cekpSSHbkdhrYYN99JHb+ cSgs5GrjI3RPIlMYpUrs4yaRk3Ug5Be1S+0l7FwZlEJymf/kHzyWGlc7r9s3fSnxl/raeVgk23y+r VsDpZ1c4YESg5eT1WDC11thS+XFHRDCJ3CifSvj4lbdgotv1dfj6fg7vXfK4v410uWgniRW5QWDcd KLp1eGDA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vWXwe-0000000A8tu-1qWo; Fri, 19 Dec 2025 10:42:48 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vWXwc-0000000A8tW-3DNJ for linux-arm-kernel@lists.infradead.org; Fri, 19 Dec 2025 10:42:47 +0000 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 2DF2C106F; Fri, 19 Dec 2025 02:42:37 -0800 (PST) Received: from localhost (e132581.arm.com [10.1.196.87]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id DE2FB3F5CA; Fri, 19 Dec 2025 02:42:43 -0800 (PST) Date: Fri, 19 Dec 2025 10:42:41 +0000 From: Leo Yan To: yuanfang zhang Cc: Suzuki K Poulose , Mike Leach , James Clark , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Mathieu Poirier , Leo Yan , Alexander Shishkin , Bjorn Andersson , Konrad Dybcio , kernel@oss.qualcomm.com, coresight@lists.linaro.org, linux-arm-kernel@lists.infradead.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org, maulik.shah@oss.qualcomm.com, Jie Gan Subject: Re: [PATCH v2 00/12] coresight: Add CPU cluster funnel/replicator/tmc support Message-ID: <20251219104241.GB9788@e132581.arm.com> References: <20251218-cpu_cluster_component_pm-v2-0-2335a6ae62a0@oss.qualcomm.com> <20251218104027.GA1790402@e132581.arm.com> <927f15d5-da2a-4282-b80f-c1c7563a4367@oss.qualcomm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <927f15d5-da2a-4282-b80f-c1c7563a4367@oss.qualcomm.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20251219_024246_847425_D866614C X-CRM114-Status: GOOD ( 15.77 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Fri, Dec 19, 2025 at 09:50:18AM +0800, yuanfang zhang wrote: [...] > It is due to the particular characteristics of the CPU cluster power domain. > Runtime PM for CPU devices works little different, it is mostly used to manage hierarchical > CPU topology (PSCI OSI mode) to talk with genpd framework to manage the last CPU handling in > cluster. > It doesn’t really send IPI to wakeup CPU device (It don’t have .power_on/.power_off) callback > implemented which gets invoked from .runtime_resume callback. This behavior is aligned with > the upstream Kernel. Just for easier understanding, let me give an example: funnel0: funnel@10000000 { compatible = "arm,coresight-dynamic-funnel", "arm,primecell"; reg = <0x10000000 0x1000>; clocks = <&rpmcc RPM_SMD_QDSS_CLK>, <&rpmcc RPM_SMD_QDSS_A_CLK>; clock-names = "apb_pclk", "atclk"; power-domains = <&cluster0_pd>; } If funnel0 is bound to cluster's power domain, kernel's genPD will automatically enable cluster power domain before access registers. My understanding is your driver or firmware fails to turn on a cluster power domain without waking up a CPU (and without sending IPI). It is not a kernel issue or limitation, and no any incorrect in PSCI OSI. As Suzuki said, you might directly reply Sudeep's questions. We would confirm if any flaw in common code. > > P.s., currently you can use "taskset" as a temporary solution without > > any code change, something like: > > > > taskset -c 0 echo 1 > /sys/bus/coresight/devices/etm0/enable_source > > This can address the runtime issue, but it does not resolve the problem during the probe phase. Indeed. If you insmod mode, you might can temporarily disable idle states? exec 3<> /dev/cpu_dma_latency; echo 0 >&3 insmod exec 3<>- Thanks, Leo