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From: Mika Westerberg <mika.westerberg@linux.intel.com>
To: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: 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: Mon, 1 Jul 2019 19:15:50 +0300	[thread overview]
Message-ID: <20190701161550.GA2640@lahna.fi.intel.com> (raw)
In-Reply-To: <6191578.xJk2HsE5MX@kreacher>

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

>  	 */
> -	if (!dev_pm_smart_suspend_and_suspended(dev)) {
> -		pm_runtime_resume(dev);
> -		pci_dev->state_saved = false;
> -	}
> +	pm_runtime_resume(dev);
> +	pci_dev->state_saved = false;
>  
>  	if (pm->freeze) {
>  		int error;
> 
> 
> 

  reply	other threads:[~2019-07-01 16:15 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 [this message]
2019-07-02 15:59     ` Rafael J. Wysocki
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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