From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751996AbdBUKnE (ORCPT ); Tue, 21 Feb 2017 05:43:04 -0500 Received: from foss.arm.com ([217.140.101.70]:58278 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751325AbdBUKm6 (ORCPT ); Tue, 21 Feb 2017 05:42:58 -0500 Subject: Re: [PATCH/RFC 3/6] drivers: firmware: psci: Implement shallow suspend mode To: Geert Uytterhoeven References: <1487622809-25127-1-git-send-email-geert+renesas@glider.be> <1487622809-25127-4-git-send-email-geert+renesas@glider.be> Cc: Lorenzo Pieralisi , Mark Rutland , Lina Iyer , John Stultz , Thomas Gleixner , "Rafael J . Wysocki" , Len Brown , Pavel Machek , Rob Herring , Sudeep Holla , Magnus Damm , devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-renesas-soc@vger.kernel.org, linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org From: Sudeep Holla Organization: ARM Message-ID: <08c5dcf3-9d7c-33ff-f801-8f94f630f49b@arm.com> Date: Tue, 21 Feb 2017 10:42:45 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.7.0 MIME-Version: 1.0 In-Reply-To: <1487622809-25127-4-git-send-email-geert+renesas@glider.be> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Geert, On 20/02/17 20:33, Geert Uytterhoeven wrote: > Enable support for "shallow" suspend mode, also known as "Standby" or > "Power-On Suspend". > > As secondary CPU cores are taken offline, "shallow" suspend mode saves > slightly more power than "s2idle", but less than "deep" suspend mode. > However, unlike "deep" suspend mode, "shallow" suspend mode can be used > regardless of the presence of support for PSCI_SYSTEM_SUSPEND, which is > an optional API in PSCI v1.0. > > List the available system suspend modes: > > $ cat /sys/power/mem_sleep > s2idle shallow [deep] > > Suspend to "shallow" mode: > > $ echo shallow > /sys/power/mem_sleep > $ echo mem > /sys/power/state > I don't have the links to such previous attempts handy, but we have more elegant alternative options(suspend-to-idle) and any such attempts to hack around the PSCI will be NACKed. -- Regards, Sudeep From mboxrd@z Thu Jan 1 00:00:00 1970 From: sudeep.holla@arm.com (Sudeep Holla) Date: Tue, 21 Feb 2017 10:42:45 +0000 Subject: [PATCH/RFC 3/6] drivers: firmware: psci: Implement shallow suspend mode In-Reply-To: <1487622809-25127-4-git-send-email-geert+renesas@glider.be> References: <1487622809-25127-1-git-send-email-geert+renesas@glider.be> <1487622809-25127-4-git-send-email-geert+renesas@glider.be> Message-ID: <08c5dcf3-9d7c-33ff-f801-8f94f630f49b@arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hi Geert, On 20/02/17 20:33, Geert Uytterhoeven wrote: > Enable support for "shallow" suspend mode, also known as "Standby" or > "Power-On Suspend". > > As secondary CPU cores are taken offline, "shallow" suspend mode saves > slightly more power than "s2idle", but less than "deep" suspend mode. > However, unlike "deep" suspend mode, "shallow" suspend mode can be used > regardless of the presence of support for PSCI_SYSTEM_SUSPEND, which is > an optional API in PSCI v1.0. > > List the available system suspend modes: > > $ cat /sys/power/mem_sleep > s2idle shallow [deep] > > Suspend to "shallow" mode: > > $ echo shallow > /sys/power/mem_sleep > $ echo mem > /sys/power/state > I don't have the links to such previous attempts handy, but we have more elegant alternative options(suspend-to-idle) and any such attempts to hack around the PSCI will be NACKed. -- Regards, Sudeep