linux-kernel - Re: [PATCH 2/3] Adapt the sky2 driver to the reworked PCI PM

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Message-ID: <20080815091521.3f721d68@extreme>
Date:	Fri, 15 Aug 2008 09:15:21 -0700
From:	Stephen Hemminger <shemminger@...tta.com>
To:	"Rafael J. Wysocki" <rjw@...k.pl>
Cc:	netdev@...r.kernel.org, Andrew Morton <akpm@...ux-foundation.org>,
	Jeff Garzik <jeff@...zik.org>,
	Jesse Barnes <jbarnes@...tuousgeek.org>,
	LKML <linux-kernel@...r.kernel.org>,
	pm list <linux-pm@...ts.linux-foundation.org>,
	"Brandeburg, Jesse" <jesse.brandeburg@...el.com>,
	Stephen Hemminger <stephen.hemminger@...tta.com>
Subject: Re: [PATCH 2/3] Adapt the sky2 driver to the reworked PCI PM

On Fri, 15 Aug 2008 15:32:13 +0200
"Rafael J. Wysocki" <rjw@...k.pl> wrote:

> On Friday, 15 of August 2008, Rafael J. Wysocki wrote:
> > On Friday, 15 of August 2008, Stephen Hemminger wrote:
> > > On Thu, 14 Aug 2008 23:38:17 +0200
> > > "Rafael J. Wysocki" <rjw@...k.pl> wrote:
> > > 
> > > > Adapt the sky2 driver to the reworked PCI PM
> > > > 
> > > > * Use device_set_wakeup_enable() and friends as needed
> > > > * Remove an open-coded reference to the standard PCI PM registers
> > > > * Use pci_prepare_to_sleep() and pci_back_from_sleep() in the
> > > >   ->suspend() and ->resume() callbacks
> > > > * Use the observation that it is sufficient to call pci_enable_wake()
> > > >   once, unless it fails
> > > > 
> > > > Tested on Asus M3A32-MVP (Yukon-2 EC Ultra rev 3).
> > > > 
> > > > Signed-off-by: Rafael J. Wysocki <rjw@...k.pl>
> > > > ---
> > > >  drivers/net/sky2.c |   34 ++++++++++------------------------
> > > >  1 file changed, 10 insertions(+), 24 deletions(-)
> > > > 
> > > > Index: linux-2.6/drivers/net/sky2.c
> > > > ===================================================================
> > > > --- linux-2.6.orig/drivers/net/sky2.c
> > > > +++ linux-2.6/drivers/net/sky2.c
> > > > @@ -3035,7 +3035,8 @@ static int sky2_set_wol(struct net_devic
> > > >  	struct sky2_port *sky2 = netdev_priv(dev);
> > > >  	struct sky2_hw *hw = sky2->hw;
> > > >  
> > > > -	if (wol->wolopts & ~sky2_wol_supported(sky2->hw))
> > > > +	if ((wol->wolopts & ~sky2_wol_supported(sky2->hw))
> > > > +	    || !device_can_wakeup(&hw->pdev->dev))
> > > >  		return -EOPNOTSUPP;
> > > >  
> > > 
> > > There was a regression in earlier releases caused because some BIOS's
> > > are wrong, and device can wakeup.
> > 
> > device_can_wakeup() returns 'true' if the device is capable of generating PME#
> > from at least one low power state (this is determined on the basis of the
> > contents of the device's PCI PM registers - please have a look at
> > drivers/pci/pci_pm_init() for details) or if ACPI tells us it can wake up.
> > IOW, the BIOSes opinion doesn't matter if we find that the device is capable of
> > generating PME#, so the regression must have been related to something else.
> > I'm very interested in the details, if available.
> > 
> > Of course, since we rely on the ability of the device to generate PME# and
> > device_can_wakeup() returning 'false' means that the device cannot generate
> > PME# from any state, it's reasonable to check it IMO.
> 
> BTW, if device_can_wakeup(&pdev->dev) returns 'false',
> pci_enable_wake(pdev, state, true) will fail for any 'state', so the wake-up
> won't work regardless of the change above.
> 
> Thanks,
> Rafael

Okay, the problem was false positives from ACPI. It looks like this won't make
the problem any worse.
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