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From: "Rafael J. Wysocki" <rafael@kernel.org>
To: Lukas Wunner <lukas@wunner.de>
Cc: Bjorn Helgaas <helgaas@kernel.org>,
	Konstantin Kharlamov <Hi-Angel@yandex.ru>,
	Linux PCI <linux-pci@vger.kernel.org>,
	"Rafael J. Wysocki" <rjw@rjwysocki.net>,
	Andreas Noever <andreas.noever@gmail.com>,
	Linux PM <linux-pm@vger.kernel.org>
Subject: Re: [PATCH] PCI: don't power-off apple thunderbolt controller on s2idle
Date: Fri, 7 May 2021 11:51:20 +0200	[thread overview]
Message-ID: <CAJZ5v0hFEX3doAPbDDix3oGpfCbSkWLgjPzNdvNLXyNRN+uqzQ@mail.gmail.com> (raw)
In-Reply-To: <20210506220738.GA2150@wunner.de>

On Fri, May 7, 2021 at 12:07 AM Lukas Wunner <lukas@wunner.de> wrote:
>
> On Thu, May 06, 2021 at 04:48:42PM -0500, Bjorn Helgaas wrote:
> > On Thu, May 06, 2021 at 08:38:20PM +0300, Konstantin Kharlamov wrote:
> > > On Macbook 2013 resuming from s2idle results in external monitor no
> > > longer being detected, and dmesg having errors like:
> > >
> > >     pcieport 0000:06:00.0: can't change power state from D3hot to D0 (config space inaccessible)
> > >
> > > and a stacktrace. The reason turned out that the hw that the quirk
> > > powers off does not get powered on back on resume.
> >
> > quirk_apple_poweroff_thunderbolt() was added in 2014 by 1df5172c5c25
> > ("PCI: Suspend/resume quirks for Apple thunderbolt").  It claims
> > "power is automatically restored before resume," so there must be
> > something special about s2idle that prevents the power-on.
>
> With s2idle, the machine isn't suspended via ACPI, so the AML code
> which powers the controller off isn't executed.  The dance to prepare
> the controller for power-off consequently isn't necessary but rather
> harmful.
>
> To get the same power savings as with ACPI suspend, the controller
> needs to be powered off via runtime suspend.

I'm not quite sure why runtime PM needs to be involved.

The controller suspend can happen in the system-wide suspend code path directly.

> I posted patches for
> that back in 2016.  I'm using them on my laptop, they need some
> polishing and rebasing before I can repost them due to massive
> changes that have happened in the thunderbolt driver in the meantime.
> Without these patches, the controller sucks 1.5W of power in s2idle.
>
> > Obviously the *hardware* hasn't changed since 1df5172c5c25.  Is s2idle
> > something that wasn't tested back then, or is this problem connected
> > to an s2idle change since then?  Can we identify a commit that
> > introduced this problem?  That would help with backporting or stable
> > tags.
>
> Yes I believe the quirk predates the introduction of s2idle by a couple
> of years.
>
> > > Signed-off-by: Konstantin Kharlamov <Hi-Angel@yandex.ru>
>
> Reviewed-by: Lukas Wunner <lukas@wunner.de>
>
> The patch looks fine to me.
>
> Thanks,
>
> Lukas

  reply	other threads:[~2021-05-07  9:51 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-06 17:38 [PATCH] PCI: don't power-off apple thunderbolt controller on s2idle Konstantin Kharlamov
2021-05-06 21:48 ` Bjorn Helgaas
2021-05-06 22:07   ` Lukas Wunner
2021-05-07  9:51     ` Rafael J. Wysocki [this message]
2021-05-08  8:48       ` Lukas Wunner
2021-05-07 13:30     ` Bjorn Helgaas
2021-05-07 14:08       ` Konstantin Kharlamov
2021-05-12 20:36         ` Konstantin Kharlamov
2021-05-17 19:51           ` PING " Konstantin Kharlamov
2021-05-19 17:28         ` Bjorn Helgaas
2021-05-19 19:12           ` Rafael J. Wysocki
2021-05-19 19:48             ` Bjorn Helgaas
2021-05-20 11:27               ` Rafael J. Wysocki
2021-05-20 11:54                 ` Rafael J. Wysocki
2021-05-20 19:49                   ` Bjorn Helgaas
2021-05-20 23:28                     ` Konstantin Kharlamov
2021-05-24  6:59                       ` Konstantin Kharlamov
2021-05-20 23:55                     ` [PATCH v2] PCI: don't call firmware hooks on suspend unless it's fw-controlled Konstantin Kharlamov
2021-05-28  7:39                       ` PING: " Konstantin Kharlamov
2021-06-03  8:36                         ` PING: " Konstantin Kharlamov
2021-06-03 17:46                           ` Bjorn Helgaas
2021-06-04  8:30                             ` Konstantin Kharlamov
2021-05-21  9:47                     ` [PATCH] PCI: don't power-off apple thunderbolt controller on s2idle Rafael J. Wysocki
2021-05-07 15:02       ` Rafael J. Wysocki
2021-05-08  8:20       ` Lukas Wunner
2021-05-07  9:32   ` Konstantin Kharlamov
2021-05-07 13:07     ` Bjorn Helgaas
2021-05-07 13:48       ` Konstantin Kharlamov
2021-05-20 11:58   ` Rafael J. Wysocki
2021-06-07 23:17 ` Bjorn Helgaas

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