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From: "Rafael J. Wysocki" <rafael@kernel.org>
To: Mika Westerberg <mika.westerberg@linux.intel.com>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>,
	Linux PM <linux-pm@vger.kernel.org>,
	Linux PCI <linux-pci@vger.kernel.org>,
	Linux ACPI <linux-acpi@vger.kernel.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Bjorn Helgaas <helgaas@kernel.org>,
	Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
	Hans De Goede <hdegoede@redhat.com>,
	"Robert R. Howell" <RHowell@uwyo.edu>
Subject: Re: [PATCH v2 1/5] PM: ACPI/PCI: Resume all devices during hibernation
Date: Tue, 2 Jul 2019 17:59:28 +0200	[thread overview]
Message-ID: <CAJZ5v0iJ4bELn+LSLgnOaUz6d31FeCV84t=VxKYHA1hLUnQ-ZQ@mail.gmail.com> (raw)
In-Reply-To: <20190701161550.GA2640@lahna.fi.intel.com>

On Mon, Jul 1, 2019 at 6:15 PM Mika Westerberg
<mika.westerberg@linux.intel.com> wrote:
>
> On Mon, Jul 01, 2019 at 12:44:25PM +0200, Rafael J. Wysocki wrote:
> > From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> >
> > Both the PCI bus type and the ACPI PM domain avoid resuming
> > runtime-suspended devices with DPM_FLAG_SMART_SUSPEND set during
> > hibernation (before creating the snapshot image of system memory),
> > but that turns out to be a mistake.  It leads to functional issues
> > and adds complexity that's hard to justify.
> >
> > For this reason, resume all runtime-suspended PCI devices and all
> > devices in the ACPI PM domains before creating a snapshot image of
> > system memory during hibernation.
> >
> > Fixes: 05087360fd7a (ACPI / PM: Take SMART_SUSPEND driver flag into account)
> > Fixes: c4b65157aeef (PCI / PM: Take SMART_SUSPEND driver flag into account)
> > Link: https://lore.kernel.org/linux-acpi/917d4399-2e22-67b1-9d54-808561f9083f@uwyo.edu/T/#maf065fe6e4974f2a9d79f332ab99dfaba635f64c
> > Reported-by: Robert R. Howell <RHowell@uwyo.edu>
> > Tested-by: Robert R. Howell <RHowell@uwyo.edu>
> > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> > ---
> >
> > -> v2: No changes.
> >
> > ---
> >  drivers/acpi/device_pm.c |   13 +++++++------
> >  drivers/pci/pci-driver.c |   16 ++++++++--------
> >  2 files changed, 15 insertions(+), 14 deletions(-)
> >
> > Index: linux-pm/drivers/acpi/device_pm.c
> > ===================================================================
> > --- linux-pm.orig/drivers/acpi/device_pm.c
> > +++ linux-pm/drivers/acpi/device_pm.c
> > @@ -1155,13 +1155,14 @@ EXPORT_SYMBOL_GPL(acpi_subsys_resume_ear
> >  int acpi_subsys_freeze(struct device *dev)
> >  {
> >       /*
> > -      * This used to be done in acpi_subsys_prepare() for all devices and
> > -      * some drivers may depend on it, so do it here.  Ideally, however,
> > -      * runtime-suspended devices should not be touched during freeze/thaw
> > -      * transitions.
> > +      * Resume all runtime-suspended devices before creating a snapshot
> > +      * image of system memory, because the restore kernel generally cannot
> > +      * be expected to always handle them consistently and they need to be
> > +      * put into the runtime-active metastate during system resume anyway,
> > +      * so it is better to ensure that the state saved in the image will be
> > +      * alwyas consistent with that.
>
> alwyas -> always
>
> >        */
> > -     if (!dev_pm_test_driver_flags(dev, DPM_FLAG_SMART_SUSPEND))
> > -             pm_runtime_resume(dev);
> > +     pm_runtime_resume(dev);
> >
> >       return pm_generic_freeze(dev);
> >  }
> > Index: linux-pm/drivers/pci/pci-driver.c
> > ===================================================================
> > --- linux-pm.orig/drivers/pci/pci-driver.c
> > +++ linux-pm/drivers/pci/pci-driver.c
> > @@ -1012,15 +1012,15 @@ static int pci_pm_freeze(struct device *
> >       }
> >
> >       /*
> > -      * This used to be done in pci_pm_prepare() for all devices and some
> > -      * drivers may depend on it, so do it here.  Ideally, runtime-suspended
> > -      * devices should not be touched during freeze/thaw transitions,
> > -      * however.
> > +      * Resume all runtime-suspended devices before creating a snapshot
> > +      * image of system memory, because the restore kernel generally cannot
> > +      * be expected to always handle them consistently and they need to be
> > +      * put into the runtime-active metastate during system resume anyway,
> > +      * so it is better to ensure that the state saved in the image will be
> > +      * alwyas consistent with that.
>
> ditto

Thanks, I'll fix these up when applying the patch.

  reply	other threads:[~2019-07-02 15:59 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-07-01 10:42 [PATCH v2 0/5] PM: PCI/ACPI: Hibernation handling fixes Rafael J. Wysocki
2019-07-01 10:44 ` [PATCH v2 1/5] PM: ACPI/PCI: Resume all devices during hibernation Rafael J. Wysocki
2019-07-01 16:15   ` Mika Westerberg
2019-07-02 15:59     ` Rafael J. Wysocki [this message]
2019-07-02  4:24   ` Robert R. Howell
2019-07-01 10:46 ` [PATCH v2 2/5] PCI: PM: Simplify bus-level hibernation callbacks Rafael J. Wysocki
2019-07-01 10:54 ` [PATCH v2 3/5] ACPI: PM: Simplify and fix PM domain " Rafael J. Wysocki
2019-07-01 10:54 ` [PATCH v2 4/5] ACPI: PM: Introduce "poweroff" callbacks for ACPI PM domain and LPSS Rafael J. Wysocki
2019-07-01 10:55 ` [PATCH v2 5/5] ACPI: PM: Drop unused function and function header Rafael J. Wysocki
2019-07-01 11:30 ` [PATCH v2 0/5] PM: PCI/ACPI: Hibernation handling fixes Hans de Goede
2019-07-01 16:20 ` Mika Westerberg
2019-07-05  9:50   ` Rafael J. Wysocki

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