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 91ED4D6ACE7 for ; Thu, 18 Dec 2025 11:33:23 +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-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=7GgEGNIgDPOJ8Rpf9B88k6d+kWmu+f9Lca07EFk6KFM=; b=nA2WXLyFYkBsxlnH7i+9PGjySe xDN7iAUR1vK73TlgklfCNsAbyGNo1GPQwXQ2MQslD1brDAwRWf7VNpjTE+6NckuYvPh65y9WXoMhP p7H2Fioe23eDdRBgtZy5LRWnN4WMTM4St8HDqWYIvNzHuC22Kus3ufErntCH5dC3WZjwfj7KF++4r ai5ImpJqR4fUS9/vfNLs+jK/LN18EL3cVTs1nhABWhxu8pCw3xcOpCxJ6XLwUA+3xX1AiGulBYQwQ a2Gfomxyl+euKQwMYoDAvP8rMltDIm74Cm2fRN++AHxRO3jI0TjIag72edt/ieyz45aZrERLhNTl9 qWJdUXSg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vWCFy-00000008Jz1-0G4Y; Thu, 18 Dec 2025 11:33:18 +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 1vWCFv-00000008JyS-0ym2 for linux-arm-kernel@lists.infradead.org; Thu, 18 Dec 2025 11:33:16 +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 D30C8FEC; Thu, 18 Dec 2025 03:33:04 -0800 (PST) Received: from bogus (e133711.arm.com [10.1.196.55]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 9BAF13F73F; Thu, 18 Dec 2025 03:33:08 -0800 (PST) Date: Thu, 18 Dec 2025 11:33:05 +0000 From: Sudeep Holla To: Yuanfang Zhang Cc: Suzuki K Poulose , Sudeep Holla , 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: <20251218-careful-ruby-wildebeest-a8babd@sudeepholla> References: <20251218-cpu_cluster_component_pm-v2-0-2335a6ae62a0@oss.qualcomm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20251218-cpu_cluster_component_pm-v2-0-2335a6ae62a0@oss.qualcomm.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20251218_033315_316544_73D6E834 X-CRM114-Status: GOOD ( 14.19 ) 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 Thu, Dec 18, 2025 at 12:09:40AM -0800, Yuanfang Zhang wrote: > This patch series adds support for CoreSight components local to CPU clusters, > including funnel, replicator, and TMC, which reside within CPU cluster power > domains. These components require special handling due to power domain > constraints. > Could you clarify why PSCI-based power domains associated with clusters in domain-idle-states cannot address these requirements, given that PSCI CPU-idle OSI mode was originally intended to support them? My understanding of this patch series is that OSI mode is unable to do so, which, if accurate, appears to be a flaw that should be corrected. > Unlike system-level CoreSight devices, these components share the CPU cluster's > power domain. When the cluster enters low-power mode (LPM), their registers > become inaccessible. Notably, `pm_runtime_get` alone cannot bring the cluster > out of LPM, making standard register access unreliable. > Are these devices the only ones on the system that are uniquely bound to cluster-level power domains? If not, what additional devices share this dependency so that we can understand how they are managed in comparison? > To address this, the series introduces: > - Identifying cluster-bound devices via a new `qcom,cpu-bound-components` > device tree property. Really, no please. -- Regards, Sudeep