Date:	Thu, 10 May 2012 22:14:20 +0200
From:	"Rafael J. Wysocki" <rjw@...k.pl>
To:	Len Brown <lenb@...nel.org>
Cc:	Bjorn Helgaas <bhelgaas@...gle.com>, Len Brown <lenb@...nel.org>,
	ACPI Devel Mailing List <linux-acpi@...r.kernel.org>,
	Linux PM list <linux-pm@...r.kernel.org>,
	linux-pci@...r.kernel.org, Alan Stern <stern@...land.harvard.edu>,
	"Oleksij Rempel (fishor)" <bug-track@...her-privat.net>,
	LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] ACPI / PCI: Make _SxD/_SxW check follow ACPI 4.0a spec

On Monday, April 30, 2012, Rafael J. Wysocki wrote:
> On Monday, April 30, 2012, Bjorn Helgaas wrote:
> > On Sun, Apr 29, 2012 at 2:44 PM, Rafael J. Wysocki <rjw@...k.pl> wrote:
> > > From: Oleksij Rempel <bug-track@...her-privat.net>
> > >
> > > This patch makes _SxD/_SxW check follow the ACPI 4.0a specification
> > > more closely and fixes suspend bug found on ASUS Zenbook UX31E.
> > >
> > > Some OEM use _SxD fileds do blacklist brocken Dx states.
> > > If _SxD/_SxW return values are check before suspend as appropriate,
> > > some nasty suspend/resume issues may be avoided.
> > >
> > > References: https://bugzilla.kernel.org/show_bug.cgi?id=42728
> > > Signed-off-by: Oleksij Rempel <bug-track@...her-privat.net>
> > > Signed-off-by: Rafael J. Wysocki <rjw@...k.pl>
> > > ---
> > >
> > > Bjorn, Len,
> > >
> > > This is -stable material and therefore v3.4 as well, IMO.  Please let me
> > > know if one of you can take it or whether you want me to handle it all the
> > > way to Linus.
> > 
> > I'm OK with this from a PCI perspective.  Most of the change is in
> > ACPI, so I propose that either you or Len take care of it.
> > 
> > The second paragraph of the changelog has several typos
> > (fileds/fields, do/to, brocken/broken, etc).
> 
> Thanks for spotting that, the version below should be better.
> 
> I'll wait for Len to respond till Friday and will take care of the patch myself
> if he doesn't say anything.
> 
> May I assume an ACK from you?
> 
> Rafael
> 
> ---
> From: Oleksij Rempel <bug-track@...her-privat.net>
> Subject: ACPI / PCI: Make _SxD/_SxW check follow ACPI 4.0a spec
> 
> This patch makes _SxD/_SxW check follow the ACPI 4.0a specification
> more closely and fixes suspend bug found on ASUS Zenbook UX31E.
> 
> Some OEM use _SxD fields to blacklist broken device Dx states, so
> if _SxD/_SxW return values are checked before suspend as appropriate,
> some nasty suspend/resume issues may be avoided.
> 
> References: https://bugzilla.kernel.org/show_bug.cgi?id=42728
> Signed-off-by: Oleksij Rempel <bug-track@...her-privat.net>
> Signed-off-by: Rafael J. Wysocki <rjw@...k.pl>

Len, this is an important fix, any chance to take it for v3.5 and -stable?
Or do you want me to do that?

Rafael


> ---
>  drivers/acpi/sleep.c |   22 +++++++++++++++++++++-
>  drivers/pci/pci.c    |   12 +++++++++++-
>  2 files changed, 32 insertions(+), 2 deletions(-)
> 
> Index: linux/drivers/acpi/sleep.c
> ===================================================================
> --- linux.orig/drivers/acpi/sleep.c
> +++ linux/drivers/acpi/sleep.c
> @@ -720,10 +720,30 @@ int acpi_pm_device_sleep_state(struct de
>  	 *
>  	 * NOTE: We rely on acpi_evaluate_integer() not clobbering the integer
>  	 * provided -- that's our fault recovery, we ignore retval.
> +	 *
> +	 * According to ACPI 4.0a (April 5, 2010), page 294,
> +	 * Table 7-7 S3 Action / Result Table, we need to evaluate _SxW in
> +	 * addition to _SxD if the device is configured for wakeup:
> +	 * Desired Action    | _S3D | _PRW | _S3W | Resultant D-state
> +	 * Enter S3          |  N/A |  D/C |  N/A | OSPM decides
> +	 * Enter S3, No Wake |   2  |  D/C |  D/C | Enter D2 or D3
> +	 * Enter S3, Wake    |   2  |   3  |  N/A | Enter D2
> +	 * Enter S3, Wake    |   2  |   3  |   3  | Enter D2 or D3
> +	 * Enter S3, Wake    |  N/A |   3  |   2  | Enter D0, D1 or D2
>  	 */
> -	if (acpi_target_sleep_state > ACPI_STATE_S0)
> +	if (acpi_target_sleep_state > ACPI_STATE_S0) {
> +		acpi_status status;
> +
>  		acpi_evaluate_integer(handle, acpi_method, NULL, &d_min);
>  
> +		if (device_may_wakeup(dev)) {
> +			acpi_method[3] = 'W';
> +			status = acpi_evaluate_integer(handle, acpi_method,
> +						       NULL, &d_max);
> +			if (ACPI_FAILURE(status))
> +				d_max = d_min;
> +		}
> +	}
>  	/*
>  	 * If _PRW says we can wake up the system from the target sleep state,
>  	 * the D-state returned by _SxD is sufficient for that (we assume a
> Index: linux/drivers/pci/pci.c
> ===================================================================
> --- linux.orig/drivers/pci/pci.c
> +++ linux/drivers/pci/pci.c
> @@ -1691,10 +1691,20 @@ pci_power_t pci_target_state(struct pci_
>  {
>  	pci_power_t target_state = PCI_D3hot;
>  
> -	if (platform_pci_power_manageable(dev)) {
> +	/*
> +	 * According to ACPI 4.0a,7.2 Device Power Management Objects, device
> +	 * with wake capability should have _PRW or _PSW object and can have
> +	 * _SxD or _SxW object.
> +	 * It looks like some OEMs use this fields to avoid buggy Dx states
> +	 * of devices, so we need to check for _PRW or _PSW and see if _SxD or
> +	 * _SxW indicate to overwrite Dx.
> +	 */
> +	if (platform_pci_power_manageable(dev)
> +	    || platform_pci_can_wakeup(dev)) {
>  		/*
>  		 * Call the platform to choose the target state of the device
>  		 * and enable wake-up from this state if supported.
> +		 * (Check _SxD and _SxW)
>  		 */
>  		pci_power_t state = platform_pci_choose_state(dev);
>  
> --
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