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 ED922E7719E for ; Mon, 13 Jan 2025 10:32:56 +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=AUjut5G7ewo0W3DwgvTi4atJ8dPOpW5TupiydsaLSXg=; b=a6Qli/wrYWgpPIkMPmEDfkRFjy YFnwplBvGbwAAAyRyTsyii0BlFBSeYGkY1wLMnGW3LiGErnwcEFk0pGb1SjbQoFH50zJVojFqrJoI zf9sCg9t5JumwChhIdxmYOPZ4OlwAfajvEooMbSZHi6zKxyfEF3dI/K4KU35IJF5DsWsH2LhmcpML CpE0Q9Di/Mk7j8WuLbr59+Po7kct2AJaZqA/btLhtC558gBeTFguNWOzGxN+MhhFuj7RDUCTUt2UL O0xBIgQ3rdlTEY2of7MS4WDIP8pbgHcOaWc9WaSeMrM0uOV5gAocAJlVJrRZbeNobmqNgXqpxo96k lupT6kpQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1tXHkR-00000004nX2-2AkI; Mon, 13 Jan 2025 10:32:43 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1tXHjD-00000004nNL-2sJ6 for linux-arm-kernel@lists.infradead.org; Mon, 13 Jan 2025 10:31:28 +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 9CB371424; Mon, 13 Jan 2025 02:31:53 -0800 (PST) Received: from bogus (e133711.arm.com [10.1.196.55]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id C5B243F66E; Mon, 13 Jan 2025 02:31:23 -0800 (PST) Date: Mon, 13 Jan 2025 10:31:21 +0000 From: Sudeep Holla To: "Peng Fan (OSS)" Cc: , , Sudeep Holla , , , , , , Peng Fan Subject: Re: [PATCH] pmdomain: arm: scmi_pm_domain: Initialize state as off Message-ID: References: <20250110061346.2440772-1-peng.fan@oss.nxp.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250110061346.2440772-1-peng.fan@oss.nxp.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250113_023127_763978_E475D58D X-CRM114-Status: GOOD ( 10.85 ) 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, Jan 10, 2025 at 02:13:46PM +0800, Peng Fan (OSS) wrote: > From: Peng Fan > > Per ARM SCMI Spec DEN0056E, page 16, "The platform may disable a resource > if no agent has requested to use that resource." > True, but ... > Linux Kernel should not rely on a state that it has not requested, so > make state as off during initialization. > IIUC, this was done to avoid any transitions if the bootloader like U-Boot has turned on the resource and OS can just rely on that stay. Anyways if the resource is not used by any driver/device in the kernel, won't it be turned off anyways ? What am I missing ? I need to dig details, but I remember doing what this patch does and reverting to what we have based on the feedback IIRC. -- Regards, Sudeep