From: "Rafael J. Wysocki" <rjw@rjwysocki.net>
To: Tom Lanyon <tom@oneshoeco.com>
Cc: Linux ACPI <linux-acpi@vger.kernel.org>,
        Linux PM <linux-pm@vger.kernel.org>,
        Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        Darren Hart <dvhart@infradead.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>,
        Mika Westerberg <mika.westerberg@linux.intel.com>,
        Mario Limonciello <mario.limonciello@dell.com>,
        =?ISO-8859-1?Q?J=E9r=F4me?= de Bretagne 
        <jerome.debretagne@gmail.com>,
        "Zheng, Lv" <lv.zheng@intel.com>,
        Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [PATCH] ACPI / sleep: EC-based wakeup from suspend-to-idle on recent systems
Date: Tue, 27 Jun 2017 17:03:48 +0200
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On Tuesday, June 27, 2017 03:50:33 PM Tom Lanyon wrote:
> On 23 June 2017 at 12:40, Linus Torvalds <torvalds@linux-foundation.org> wrote:
> > On Thu, Jun 22, 2017 at 4:56 PM, Rafael J. Wysocki <rjw@rjwysocki.net> wrote:
> >>
> >> Some recent Dell laptops, including the XPS13 model numbers 9360 and
> >> 9365, cannot be woken up from suspend-to-idle by pressing the power
> >> button which is unexpected and makes that feature less usable on
> >> those systems.  [ details removed ]
> >
> > This looks much more reasonable and more likely to work on future machines too.
> >
> > Of course, who knows what broken machines it will cause problems on,
> > but it sounds like the code now does what it's supposed to and what
> > Win10 does, so maybe it JustWorks(tm). Hah.
> 
> Rafael - thanks for your efforts on this.

You're welcome!

> I wanted to provide some feedback from some quick and naive tests on
> an XPS 13 9365 in case it was useful, as it seems like there's still
> some way to go before matching Win10's behaviour.
> 
>     Linux idling w/ screen ON => 17% battery drain per hour.
>     Linux idling w/ screen OFF => 12% battery drain per hour.
>     Linux during s2idle => 6% battery drain per hour.
>     Win10 during sleep => 1% battery drain per hour.
> 
> where Linux = 4.12-rc6 + the latest patch from your acpi-pm-test branch.
> 
> So whilst s2idle halves the battery drain compared to the machine
> staying powered on, it's still significantly more draining than Win10.

Thanks for the data.

> Let me know if there's any more useful analysis I can do.

I would carry out s2idle under turbostat to see how much PC10 residency is
there while suspended.  That may be a significant factor.

Most likely there is a device preventing the SoC from reaching its deepest
low-power states under Linux on your system and it needs to be identified
and dealt with.

Thanks,
Rafael