From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dennis Wassenberg Subject: Re: S0iX Ultra Low Power States Date: Thu, 4 Dec 2014 10:59:50 +0100 Message-ID: <54803096.6070807@secunet.com> References: <54747B59.2080503@secunet.com> <20141125101359.088cdacf@kcaccard-desk.amr.corp.intel.com> <54770FF3.4000809@secunet.com> Mime-Version: 1.0 Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 8bit Return-path: Received: from a.mx.secunet.com ([195.81.216.161]:52510 "EHLO a.mx.secunet.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753219AbaLDKAP (ORCPT ); Thu, 4 Dec 2014 05:00:15 -0500 In-Reply-To: <54770FF3.4000809@secunet.com> Sender: linux-pm-owner@vger.kernel.org List-Id: linux-pm@vger.kernel.org To: Kristen Carlson Accardi Cc: "linux-pm@vger.kernel.org" Hi Kristen, Now I am investigating on an other device (Microsoft Surface Pro 3). There I followed your instructions but without success. Even powertop assumes that everything is tuned for low power. This device takes 2.5 Watt in freeze mode. So I assume that the S0i3 state was not entered automatically. Is there any possibility to check which precondition is not satisfied? Or can I force the system to enter S0iX states? Thank you & best regards, Dennis On 27.11.2014 12:50, Dennis Wassenberg wrote: > Hi Kristen, > > thank you for these hints. Especially these regarding PCIe endpoint > devices. I found that some of these was configured to be always on which > prevents the system from entering the S0iX states. After changing this > the power consumption reduced to approximately 0.5 Watt. > > Thank you & best regards, > > Dennis > > On 25.11.2014 19:13, Kristen Carlson Accardi wrote: >> On Tue, 25 Nov 2014 13:51:37 +0100 >> Dennis Wassenberg wrote: >> >>> Hi, >>> >>> I would like to know more about the Linux power management in >>> correlation to the Intel S0iX Ultra Low Power States. >>> >>> Systems which have a Windows 8 Logo must support Connected Standby (or >>> InstantGo, however it is called). One of the requirements getting this >>> logo is that the ACPI firmware must not provide an S3 object in the root >>> of the namespace. This means that Linux can not use the S3 mode. >>> >>> To archive a very low power consumption Microsoft uses the Ultra Low >>> Power States S0i1 and S0i3. Is there a way to use these low power states >>> in linux for Haswell/LynxPoint or Broadwell/Skylake platforms? >>> >>> I read something about these states. Such that they can be activated >>> automatically but there are some preconditions (e.g. certain IO devices >>> have to put into a low power state, graphics off, only one CPU online, >>> ...). If I enter the S1 Low Power State (with additional >>> disable_nonboot_cpus) all of these preconditions should be fulfilled?! >>> But I can not observe that the there is a power consumption less than 1 >>> Watt. >>> >>> Thank you & Best regards, >>> >>> Dennis >> >> Hi, >> On haswell ULT and Broadwell ULT these states can be entered as part of >> Linux's normal Idle flow if some preconditions are met. You should run >> powertop to ensure that all devices are tuned for low power. The >> embedded display must be off. (no external display connected). You >> should confirm that all PCIe endpoint devices on your platform support >> ASPM and L1 substates (using lspci). If they do not, you must ensure >> they are in D3. You should kill or freeze any processes that frequently >> wake in order to improve your average battery life. You can use >> powertop or turbostat to confirm entry into pc8/pc9/pc10. >> >> Good luck. >> Kristen >> >> > -- > To unsubscribe from this list: send the line "unsubscribe linux-pm" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html >