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

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Date:	Mon, 25 Mar 2013 09:45:51 -0700
From:	Sarah Sharp <sarah.a.sharp@...ux.intel.com>
To:	"Rafael J. Wysocki" <rjw@...k.pl>
Cc:	Bjorn Helgaas <bhelgaas@...gle.com>,
	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>,
	"Accardi, Kristen C" <kristen.c.accardi@...el.com>,
	"Huang, Ying" <ying.huang@...el.com>, linux-pci@...r.kernel.org
Subject: Re: [PATCH] PCI / ACPI: Always resume devices on ACPI wakeup
 notifications

On Sat, Mar 23, 2013 at 03:33:03PM +0100, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
> 
> It turns out that _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.
> 
> 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>

Should this be marked for stable?  I had this issue on 3.7 and 3.8 as
well.

Sarah

> ---
>  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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