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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id A30B3C001DC for ; Mon, 17 Jul 2023 16:26:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229868AbjGQQ0l (ORCPT ); Mon, 17 Jul 2023 12:26:41 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38128 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229555AbjGQQ0k (ORCPT ); Mon, 17 Jul 2023 12:26:40 -0400 Received: from mo4-p02-ob.smtp.rzone.de (mo4-p02-ob.smtp.rzone.de [81.169.146.169]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C240A130; Mon, 17 Jul 2023 09:26:38 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1689611196; cv=none; d=strato.com; s=strato-dkim-0002; b=QVbDOm9T1/eZemCIbbN7zfSwXDhyCIb+MjF5Ms25zOROvdiX7NvPBzjiTmzD8SUpye oV0EiUUOFCmkHekwCU8cX6whNANex5c/RC9llizXcyz2LMs2v9LBvbRk89BSB8+ErBtZ OmnSR2MKmGEKK7vL/dh2gmEiUkQ+erOkWcnHc0zwONLggNkvk+MV7oGRdO+3izFnNI9P gxD+3iG3wzZ/dzVGW1yqkBFNoSGknJdF+7AIHte/qD7C6yWOlGzYfOcsJwBjuPNTP/no Z/nbQsEktQ6K3c2rsWaFCKtUdDY2T4qX1ocvlUcJeHwjWhmo3g9sJLyPmUIbnma5WgXe 8JlQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; t=1689611196; s=strato-dkim-0002; d=strato.com; h=In-Reply-To:References:Message-ID:Subject:Cc:To:From:Date:Cc:Date: From:Subject:Sender; bh=O98qDLMJ/G7bcyZeLAHWml5uk/qDNSzk4LE86nK2TL0=; b=Vu5LVbW8zhKROfWRga4j6zDjwLuGfUBDuU0Q1K8RNXklI5ZXz33/womuZ/mLbNOYf+ EZlVQhH6vYqEinI9e9S30tQUzH9f5RL+fWeuX2ewwfwFh2Ewlfe52FYL1jRUiaKj198X gQ5gDBHmFP/2LyryIFSgkbFeVXLaux2h9OT1dTGK3/LWUsWnML75vLYc8TexQcfx1S5c zfZD3IMZwSiMFQ2cg91wC52s7gWi7C6rIdo5xUpMoUZKhIfBzwZdO0GqNIpO/7CDSrXg IgEZI9IPfa/V4Wv1RKtHLqJsXyIYmEPu/b5jYfH5k+pRf1qHrv6iY5wQM3UTXltE5q2X zR3w== ARC-Authentication-Results: i=1; strato.com; arc=none; dkim=none X-RZG-CLASS-ID: mo02 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; t=1689611196; s=strato-dkim-0002; d=gerhold.net; h=In-Reply-To:References:Message-ID:Subject:Cc:To:From:Date:Cc:Date: From:Subject:Sender; bh=O98qDLMJ/G7bcyZeLAHWml5uk/qDNSzk4LE86nK2TL0=; b=kEGro6C7Ic8Yyfxb0cLrAEc28tLl02bxJoK0XE0dQtU63QqW06L6f1aX05NRqn43MM loyh5uXE+9vNd1rlS4pcA1Vl7tr7UAmDYjk5IlNGm3McfaDciXxi3g7oocOG/VBF46oU D6hYIB/XhMygHdLJXbDe+KV3QZzhyQASswCrpgExXEc6gqSJDUAhgf/cHGP4iHR1rd68 V68HMOkK+vTYg2HaaHbFjFQXjbIk9PSK7toTPo9nmEtHFEDAW4RYnanmnRCWTUuc+p3G wcS/eNzYXQ6A4PrD/esp8wyrK630hpOPPccEGqZHGVO85qzLBxeRDpPp8DsJFZyr2Qx2 gvkg== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; t=1689611196; s=strato-dkim-0003; d=gerhold.net; h=In-Reply-To:References:Message-ID:Subject:Cc:To:From:Date:Cc:Date: From:Subject:Sender; bh=O98qDLMJ/G7bcyZeLAHWml5uk/qDNSzk4LE86nK2TL0=; b=VLxMrAb3DfRFu3tYoygzsdQrZKvmMwtG0ROeSnJ5PD3TUbECIfFgPEmwdBFd0or3jD WvbVsJeha/z5/x56fmCA== X-RZG-AUTH: ":P3gBZUipdd93FF5ZZvYFPugejmSTVR2nRPhVOQ/OcYgojyw4j34+u261EJF5OxJD4paA8Z2L1A==" Received: from gerhold.net by smtp.strato.de (RZmta 49.6.0 DYNA|AUTH) with ESMTPSA id D0d0a8z6HGQaZCI (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256 bits)) (Client did not present a certificate); Mon, 17 Jul 2023 18:26:36 +0200 (CEST) Date: Mon, 17 Jul 2023 18:26:35 +0200 From: Stephan Gerhold To: Konrad Dybcio Cc: Bjorn Andersson , Andy Gross , Michael Turquette , Stephen Boyd , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Marijn Suijten , linux-arm-msm@vger.kernel.org, linux-clk@vger.kernel.org, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org Subject: Re: [PATCH 04/15] clk: qcom: gcc-sm6375: Add runtime PM Message-ID: References: <20230717-topic-branch_aon_cleanup-v1-0-27784d27a4f4@linaro.org> <20230717-topic-branch_aon_cleanup-v1-4-27784d27a4f4@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230717-topic-branch_aon_cleanup-v1-4-27784d27a4f4@linaro.org> Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org On Mon, Jul 17, 2023 at 05:19:11PM +0200, Konrad Dybcio wrote: > The GCC block on SM6375 is powered by the VDD_CX rail. We need to ensure > that it's enabled to prevent unwanted power collapse. > > Enable runtime PM to keep the power flowing only when necessary. > Are you sure this is necessary? If VDD_CX was really possible to fully "power collapse" then I would expect that you lose all register settings. This is not something we want or can even handle for GCC. You would need to restore all frequency settings, branch bits etc etc. Otherwise it's a retention state, but these are covered by the corners/levels, not the enable/disable state. I think most of these power domains are effectively always-on. The important part is voting for minimal corners/levels so they can go to minimal retention state with vlow/vmin. Thanks, Stephan