Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
MIME-Version: 1.0
References: <8003272.NyiUUSuA9g@kreacher> <1798761.CQOukoFCf9@kreacher> <CAHp75VdoFwH2sQT6dwz4BCorkgJgmYEBHq-+YpT18HZx2cpmrA@mail.gmail.com>
In-Reply-To: <CAHp75VdoFwH2sQT6dwz4BCorkgJgmYEBHq-+YpT18HZx2cpmrA@mail.gmail.com>
From:   "Rafael J. Wysocki" <rafael@kernel.org>
Date:   Mon, 20 Sep 2021 12:57:27 +0200
Message-ID: <CAJZ5v0iRviZkLzRP0t2f4q5oY9y6CxRotDnyBVBt-QBt-uYReQ@mail.gmail.com>
Subject: Re: [PATCH v1 1/5] PCI: PM: x86: Drop Intel MID PCI PM support
To:     Andy Shevchenko <andy.shevchenko@gmail.com>
Cc:     "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>
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

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:
> >
> > From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> >
> > Support for Intel MID platforms has mostly gone away with the SFI
> > support removal in commit 4590d98f5a4f ("sfi: Remove framework for
> > deprecated firmware"), but there are some pieces of it still in the
> > tree.  One of them is the MID PCI PM support code which gets in the
> > way of subsequent PCI PM simplifications and trying to update it is
> > rather pointless, so get rid of it completely along with the arch
> > code pieces that are only used by it.
> >
> > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> > ---
> >
> > 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 looks like
this relies on a specific ordering of arch_initcall() calls for
correctness which is sort of fragile.