From: Kristen Carlson Accardi <kristen@linux.intel.com>
To: Dennis Wassenberg <dennis.wassenberg@secunet.com>
Cc: "linux-pm@vger.kernel.org" <linux-pm@vger.kernel.org>
Subject: Re: S0iX Ultra Low Power States
Date: Tue, 25 Nov 2014 10:13:59 -0800 [thread overview]
Message-ID: <20141125101359.088cdacf@kcaccard-desk.amr.corp.intel.com> (raw)
In-Reply-To: <54747B59.2080503@secunet.com>
On Tue, 25 Nov 2014 13:51:37 +0100
Dennis Wassenberg <dennis.wassenberg@secunet.com> 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
next prev parent reply other threads:[~2014-11-25 18:14 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-11-25 12:51 S0iX Ultra Low Power States Dennis Wassenberg
2014-11-25 18:13 ` Kristen Carlson Accardi [this message]
2014-11-27 11:50 ` Dennis Wassenberg
2014-12-04 9:59 ` Dennis Wassenberg
2014-12-04 19:25 ` Kristen Carlson Accardi
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