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=-5.6 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 4B03BC43457 for ; Mon, 12 Oct 2020 13:43:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E957E2222F for ; Mon, 12 Oct 2020 13:43:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1602510210; bh=rTaWeqywKyHZNaFmITXkZVv9/PkyyIX816PW7SNWlxw=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=1Bpjh4F3YzZ+dHrhjwMtZ4cZKz611rhb61Fl3GWfNIvo7rBjCB++a7tDtgIn/oO4C XISb0kh0pazoHZjXx5RFtvpIg87hIZ+3lQanNlL7woE9Hyc1TyA3VpnSFRgumnMcmX zp+idZO3p18ZZiJp6G4UD/Jq1XNPp5t+sH6fJki4= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389337AbgJLNn3 (ORCPT ); Mon, 12 Oct 2020 09:43:29 -0400 Received: from mail.kernel.org ([198.145.29.99]:47114 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388714AbgJLNmQ (ORCPT ); Mon, 12 Oct 2020 09:42:16 -0400 Received: from localhost (fw-tnat.cambridge.arm.com [217.140.96.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 764AE208B8; Mon, 12 Oct 2020 13:42:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1602510136; bh=rTaWeqywKyHZNaFmITXkZVv9/PkyyIX816PW7SNWlxw=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=txq0RQbtTjH1t5L8PQng/aUUdcMyaEzgTF+Wdyor97lV/8MLcOQW522Cc7p0+wZIh QTgQ6Gds2xMhmUY9a0ADQL9x8mq6x4TVtK/rmyZg/9pVApNdabFVzRmVn14HHBvRTh k8+7TagrYe2Q2oWy43gCLXwEkUklTz+syiyCL4Fs= Date: Mon, 12 Oct 2020 14:42:11 +0100 From: Mark Brown To: Sascha Hauer Cc: Christian Eggers , Shawn Guo , Pengutronix Kernel Team , Fabio Estevam , NXP Linux Team , linux-spi@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Clark Wang Subject: Re: [PATCH] spi: imx: Revert "spi: imx: enable runtime pm support" Message-ID: <20201012134211.GE4332@sirena.org.uk> References: <20201009042738.26602-1-ceggers@arri.de> <20201009073944.GA11648@pengutronix.de> <2670390.HS4A6M72fu@n95hx1g2> <20201012132821.GE11648@pengutronix.de> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="C94crkcyjafcjHxo" Content-Disposition: inline In-Reply-To: <20201012132821.GE11648@pengutronix.de> X-Cookie: Fremen add life to spice! User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --C94crkcyjafcjHxo Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Mon, Oct 12, 2020 at 03:28:21PM +0200, Sascha Hauer wrote: > On Mon, Oct 12, 2020 at 12:59:34PM +0200, Christian Eggers wrote: > > What is the benefit of controlling the SPI clock with runtime PM instead of > > doing it manually? > The clocks are reconfigured less frequently with pm_runtime. Especially > when enabling/disabling PLLs are involved pm_runtime can increase > performance. In particular pm_runtime has support for deferring the actual disable so if you get lots of activity in quick succession you don't actually ever disable things until the activity stops. This can really help reduce overhead. --C94crkcyjafcjHxo Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAABCgAdFiEEreZoqmdXGLWf4p/qJNaLcl1Uh9AFAl+EXTIACgkQJNaLcl1U h9A2Igf/WNXC40I0lSAeUPBKRg2IXrUnfh2VeWaz5yiHlMmmwFIF9/ZtJWMTVQyx fXXw3bDDp4zeFexvmfjRCa8hJcF2YCZQ03LH5iq0ME7oxZ48PFZephUgbrL5TZon 8gJeup8UsLcmuNd3gapzw3ZvlRpUWIMOpNJuq9sfkKy8I62eULIKPkNM9xAZ7jqA T+kTdUrqi9WeiphNu32wFk0aDCn9xKGWTs3msPLDjJDdagbFd4woXbGWl0Hneuwi wgiSMiHQ5z8JAGq8WNaGiaS+9hXQ45OSP9XfLv3FqAW/+vXVJHyLR3EAW9qDh2ra vfCRe+uh3oLM+GCLoYwa6Nj0DRN34Q== =snZ0 -----END PGP SIGNATURE----- --C94crkcyjafcjHxo--