linux-kernel - Re: [Update][PATCH] PCI / ACPI: Always resume devices on ACPI wakeup notifications

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Date:	Wed, 3 Apr 2013 16:38:03 -0600
From:	Bjorn Helgaas <bhelgaas@...gle.com>
To:	"Rafael J. Wysocki" <rjw@...k.pl>
Cc:	ACPI Devel Maling List <linux-acpi@...r.kernel.org>,
	LKML <linux-kernel@...r.kernel.org>,
	Linux PM list <linux-pm@...r.kernel.org>,
	Len Brown <lenb@...nel.org>,
	Matthew Garrett <mjg59@...f.ucam.org>,
	Sarah Sharp <sarah.a.sharp@...ux.intel.com>,
	"Accardi, Kristen C" <kristen.c.accardi@...el.com>,
	"Huang, Ying" <ying.huang@...el.com>,
	"linux-pci@...r.kernel.org" <linux-pci@...r.kernel.org>
Subject: Re: [Update][PATCH] PCI / ACPI: Always resume devices on ACPI wakeup notifications

On Thu, Mar 28, 2013 at 3:07 PM, Rafael J. Wysocki <rjw@...k.pl> wrote:
> From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
> Subject: PCI / ACPI: Always resume devices on ACPI wakeup notifications
>
> It turns out that the _Lxx control methods provided by some BIOSes
> clear the PME Status bit of PCI devices they handle, which means that
> pci_acpi_wake_dev() cannot really use that bit to check whether or
> not the device has signalled wakeup.
>
> One symptom of the problem is, for example, that when an affected PCI
> USB controller is runtime-suspended, then plugging in a new USB device
> into one of the controller's ports will not wake up the controller,
> which should happen.
>
> For this reason, make pci_acpi_wake_dev() always attempt to resume
> the device it is called for regardless of the device's PME Status bit
> value (that bit still has to be cleared if set at this point,
> though).
>
> Reported-by: Sarah Sharp <sarah.a.sharp@...ux.intel.com>
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
> Acked-by: Matthew Garrett <mjg59@...f.ucam.org>
> Cc: 3.7+ <stable@...r.kernel.org>
> ---
>
> The changelog in this version is slightly better than in the previous one, IMHO.

I applied this to for-linus for v3.9.  Thanks!

> ---
>  drivers/pci/pci-acpi.c |   15 ++++++++-------
>  1 file changed, 8 insertions(+), 7 deletions(-)
>
> Index: linux-pm/drivers/pci/pci-acpi.c
> ===================================================================
> --- linux-pm.orig/drivers/pci/pci-acpi.c
> +++ linux-pm/drivers/pci/pci-acpi.c
> @@ -53,14 +53,15 @@ static void pci_acpi_wake_dev(acpi_handl
>                 return;
>         }
>
> -       if (!pci_dev->pm_cap || !pci_dev->pme_support
> -            || pci_check_pme_status(pci_dev)) {
> -               if (pci_dev->pme_poll)
> -                       pci_dev->pme_poll = false;
> +       /* Clear PME Status if set. */
> +       if (pci_dev->pme_support)
> +               pci_check_pme_status(pci_dev);
>
> -               pci_wakeup_event(pci_dev);
> -               pm_runtime_resume(&pci_dev->dev);
> -       }
> +       if (pci_dev->pme_poll)
> +               pci_dev->pme_poll = false;
> +
> +       pci_wakeup_event(pci_dev);
> +       pm_runtime_resume(&pci_dev->dev);
>
>         if (pci_dev->subordinate)
>                 pci_pme_wakeup_bus(pci_dev->subordinate);
>
--
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