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From: Lukas Wunner <lukas@wunner.de>
To: "Rafael J. Wysocki" <rafael@kernel.org>
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: Sat, 8 May 2021 10:48:30 +0200	[thread overview]
Message-ID: <20210508084830.GB18309@wunner.de> (raw)
In-Reply-To: <CAJZ5v0hFEX3doAPbDDix3oGpfCbSkWLgjPzNdvNLXyNRN+uqzQ@mail.gmail.com>

On Fri, May 07, 2021 at 11:51:20AM +0200, Rafael J. Wysocki wrote:
> On Fri, May 7, 2021 at 12:07 AM Lukas Wunner <lukas@wunner.de> wrote:
> > 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.

Sorry, my comments were unclear.  What I meant to say is that the
Thunderbolt runtime PM patches allow us to power the Thunderbolt
controller up or down from the OS and we can re-use that code in
the system-wide suspend code path if s2idle is used.

Without s2idle, power to the controller is cut by transitioning
to ACPI S3 or S4, which disables the controller's power rails
without OS involvement.

Thanks,

Lukas

  reply	other threads:[~2021-05-08  8:48 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
2021-05-08  8:48       ` Lukas Wunner [this message]
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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