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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 29337C433F5 for ; Mon, 4 Oct 2021 17:05:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0B4F1613AC for ; Mon, 4 Oct 2021 17:05:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238098AbhJDRHS (ORCPT ); Mon, 4 Oct 2021 13:07:18 -0400 Received: from mail.kernel.org ([198.145.29.99]:44136 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233646AbhJDRHS (ORCPT ); Mon, 4 Oct 2021 13:07:18 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 493E761381; Mon, 4 Oct 2021 17:05:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1633367128; bh=G5hoHCsSs0ocXoe0zEsFa7YLsrviOjikiHQe2cZPcIE=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=aL9kWvE1Mens/W4k9TQo8SiASeBohIf/YABW8S9d2KgBDnq2gn7OsqcPipRjhsCTS 2VkaeQQ3TaUsRuhV/2uAEYKWHUFYowik4xbwsa1/MQ9L5ddqVp7dl246dlBnkkR1jt W1FLyxpyIZsgrbCMr6824mGbbOhW2dII3LNfzAa1Y4DpztRwVOK5QF1iFZKZOy8f6g 58MI61+D5CTGmMGg0pNyui91yfmHRJAIbhvuLn1gdJChc72MEI2u2W3f0dqsX/dxqa zny2xK7iCM1GM59RD7PsTs/GvptLm8lNvz3ogKlFhTnB2TagMzmyGzmgQ5g1KhLERB AlaRsf1xeVdAA== Date: Mon, 4 Oct 2021 18:05:26 +0100 From: Mark Brown To: Jason Gunthorpe Cc: Florian Fainelli , Lino Sanfilippo , rjui@broadcom.com, sbranden@broadcom.com, bcm-kernel-feedback-list@broadcom.com, nsaenz@kernel.org, linux-spi@vger.kernel.org, linux-rpi-kernel@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, p.rosenberger@kunbus.com, linux-integrity@vger.kernel.org, stable@vger.kernel.org Subject: Re: [PATCH] spi: bcm2835: do not unregister controller in shutdown handler Message-ID: References: <20210928195657.5573-1-LinoSanfilippo@gmx.de> <20211001175422.GA53652@sirena.org.uk> <2c4d7115-7a02-f79e-c91b-3c2dd54051b2@gmx.de> <20211004131756.GW3544071@ziepe.ca> <20211004154436.GY3544071@ziepe.ca> <20211004165127.GZ3544071@ziepe.ca> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="omXKEcphJO0A+Ruq" Content-Disposition: inline In-Reply-To: <20211004165127.GZ3544071@ziepe.ca> X-Cookie: If it heals good, say it. Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org --omXKEcphJO0A+Ruq Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Mon, Oct 04, 2021 at 01:51:27PM -0300, Jason Gunthorpe wrote: > On Mon, Oct 04, 2021 at 09:36:37AM -0700, Florian Fainelli wrote: > > No please don't, I should have arguably justified the reasons why > > better, but the main reason is that one of the platforms on which this > > driver is used has received extensive power management analysis and > > changes, and shutting down every bit of hardware, including something as > > small as a SPI controller, and its clock (and its PLL) helped meet > > stringent power targets. > Huh? for device shutdown? What would this matter if the next step is > reboot or power off? On some embedded systems, especially ultra low cost ones, the system power off state might not actually involve removing all the physical power supplies for the all the chips in the system so any residual leakages or active functions will continue to consume power. Ideally the system power on/off will be triggered by a PMIC which is able to physically remove power to most other parts of the system which avoids this issue (much like the PSU in a server) but that's not always the case. --omXKEcphJO0A+Ruq Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAABCgAdFiEEreZoqmdXGLWf4p/qJNaLcl1Uh9AFAmFbNFUACgkQJNaLcl1U h9Dx9Af8DCQRph1eyeLpiMS1kEOVvwEqf8tRrtBApuuXS5tWm7zMTg5AE2lDlds0 RTtPA3rlUwtFQ81V1DRG7dRsogvl+OVWoHNa+UCqj2U4sovq6zEVKhMmerSCZhBN hfZZ80XagCRjQWzpMciVWGE5tzgVPF1Z9hkM/jYc7x1WrHa5q0CWjfu/uWSuYQWw KNyIdjh0Xgf0sMxWZLJt5mrcsYfb8wMWn+0XQy7ZXaUIC7NAKZxwmxb1LtUN5KQQ nsQJ/lUeKzEcOW0tLmXy2EU7AqlLe2L+iDbezKDjKz8UvOAvmZRuWUKmzChRUZtl DRB0HyviDdShhrRF/2ViT9Moqu5uaw== =WGIQ -----END PGP SIGNATURE----- --omXKEcphJO0A+Ruq--