linux-acpi.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: "Rafael J. Wysocki" <rafael@kernel.org>
To: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>,
	"Rafael J. Wysocki" <rjw@rjwysocki.net>,
	Linux ACPI <linux-acpi@vger.kernel.org>,
	Linux PCI <linux-pci@vger.kernel.org>,
	x86 Maintainers <x86@kernel.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Bjorn Helgaas <helgaas@kernel.org>,
	Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
	Mika Westerberg <mika.westerberg@linux.intel.com>,
	Len Brown <len.brown@intel.com>
Subject: Re: [PATCH v1 1/5] PCI: PM: x86: Drop Intel MID PCI PM support
Date: Tue, 21 Sep 2021 16:23:37 +0200	[thread overview]
Message-ID: <CAJZ5v0jxVfqraab7zO2t3LoZecasV+gy5HRfjjacVDut2OscUw@mail.gmail.com> (raw)
In-Reply-To: <CAHp75VdE3gNXy+p=8iyqyY0Ja+AHjv6zFEGwWJSXQwz+A0X1TQ@mail.gmail.com>

On Tue, Sep 21, 2021 at 2:17 PM Andy Shevchenko
<andy.shevchenko@gmail.com> wrote:
>
> On Mon, Sep 20, 2021 at 1:57 PM Rafael J. Wysocki <rafael@kernel.org> wrote:
> > On Sun, Sep 19, 2021 at 10:32 PM Andy Shevchenko
> > <andy.shevchenko@gmail.com> wrote:
> > > On Sun, Sep 19, 2021 at 9:01 AM Rafael J. Wysocki <rjw@rjwysocki.net> wrote:
>
> ...
>
> > > > I am going to post patches removing the rest of MID support from arch/x86/
> > > > and elsewhere, but that is still quite a bit of stuff and I don't want this
> > > > simple PCI PM series to depend on that work.
> > >
> > > This is still being used by MID with ACPI assisted (*) support.
> > > Hence, not ack.
> > >
> > > *) ACPI layer is provided by U-Boot and can't fulfill all possible
> > > features that ACPI may use in the Linux kernel.
> >
> > OK, good to know.
> >
> > I'm not sure how this PCI PM stuff works with ACPI.
>
> It doesn't that is the point. The PCI is very interesting there and
> what I meant is that the ACPI implementation I have provided via
> U-Boot does not cover these.

That's OK.  It just means that these devices are not power-manageable
via ACPI on the platforms in question, but the MID PCI PM code is
present in the kernel, so we don't need analogous code in AML in the
ACPI tables.

My point is that something like the v2 of this patch series
(https://lore.kernel.org/linux-acpi/1800633.tdWV9SEqCh@kreacher/T/#m1ec249724a5ad5ad358b0ed8e149e3926934955d)
is needed to prevent ACPI from overtaking the PM for the PCI devices
on the platform once we've decided to use the MID PM for them.

Now, if it is necessary to use ACPI PM for some devices and the MID PM
for other devices on the same platform, the latter needs to grow a
meaningful "power manageable" function that needs to be used in the
code as appropriate.

> If you have any hints/ideas how it may be handled, I am all ears!

  reply	other threads:[~2021-09-21 14:23 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <8003272.NyiUUSuA9g@kreacher>
2021-09-18 13:21 ` Rafael J. Wysocki
2021-09-19 20:31   ` Andy Shevchenko
2021-09-20 10:57     ` Rafael J. Wysocki
2021-09-21 12:16       ` Andy Shevchenko
2021-09-21 14:23         ` Rafael J. Wysocki [this message]
2021-09-19 21:11   ` Ferry Toth
2021-09-20 10:58     ` Rafael J. Wysocki
2021-09-18 13:23 ` [PATCH v1 2/5] PCI: ACPI: PM: Do not use pci_platform_pm_ops for ACPI Rafael J. Wysocki
2021-09-18 13:24 ` [PATCH v1 3/5] PCI: PM: Rearrange code in pci_target_state() Rafael J. Wysocki
2021-09-18 13:26 ` [PATCH v1 4/5] PCI: PM: Make pci_choose_state() call pci_target_state() Rafael J. Wysocki
2021-09-18 13:27 ` [PATCH v1 5/5] PCI: PM: ACPI: Drop unnecessary acpi_pci_power_manageable() calls Rafael J. Wysocki

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=CAJZ5v0jxVfqraab7zO2t3LoZecasV+gy5HRfjjacVDut2OscUw@mail.gmail.com \
    --to=rafael@kernel.org \
    --cc=andriy.shevchenko@linux.intel.com \
    --cc=andy.shevchenko@gmail.com \
    --cc=helgaas@kernel.org \
    --cc=len.brown@intel.com \
    --cc=linux-acpi@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-pci@vger.kernel.org \
    --cc=mika.westerberg@linux.intel.com \
    --cc=rjw@rjwysocki.net \
    --cc=x86@kernel.org \
    --subject='Re: [PATCH v1 1/5] PCI: PM: x86: Drop Intel MID PCI PM support' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).