linux-kernel - Re: [PATCH 1/5] e1000e: fix resuming from runtime-suspend

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Date:	Thu, 31 Jan 2013 02:18:31 +0100
From:	"Rafael J. Wysocki" <rjw@...k.pl>
To:	Konstantin Khlebnikov <khlebnikov@...nvz.org>
Cc:	Bjorn Helgaas <bhelgaas@...gle.com>, linux-kernel@...r.kernel.org,
	e1000-devel@...ts.sourceforge.net, linux-pci@...r.kernel.org,
	Bruce Allan <bruce.w.allan@...el.com>,
	Jeff Kirsher <jeffrey.t.kirsher@...el.com>,
	"Rafael J. Wysocki" <rafael.j.wysocki@...el.com>
Subject: Re: [PATCH 1/5] e1000e: fix resuming from runtime-suspend

On Tuesday, January 29, 2013 10:32:14 AM Konstantin Khlebnikov wrote:
> Rafael J. Wysocki wrote:
> > On Monday, January 28, 2013 04:05:33 PM Bjorn Helgaas wrote:
> >> [+cc Rafael, author of patch you cited]
> >>
> >> On Fri, Jan 18, 2013 at 4:42 AM, Konstantin Khlebnikov
> >> <khlebnikov@...nvz.org>  wrote:
> >>> Bug was introduced in commit 23606cf5d1192c2b17912cb2ef6e62f9b11de133
> >>> ("e1000e / PCI / PM: Add basic runtime PM support (rev. 4)") in v2.6.35
> >>>
> >>> Signed-off-by: Konstantin Khlebnikov<khlebnikov@...nvz.org>
> >>> Cc: e1000-devel@...ts.sourceforge.net
> >>> Cc: Jeff Kirsher<jeffrey.t.kirsher@...el.com>
> >>> Cc: Bruce Allan<bruce.w.allan@...el.com>
> >>> ---
> >>>   drivers/net/ethernet/intel/e1000e/netdev.c |   13 ++++++++-----
> >>>   1 file changed, 8 insertions(+), 5 deletions(-)
> >>>
> >>> diff --git a/drivers/net/ethernet/intel/e1000e/netdev.c b/drivers/net/ethernet/intel/e1000e/netdev.c
> >>> index fbf75fd..2853c11 100644
> >>> --- a/drivers/net/ethernet/intel/e1000e/netdev.c
> >>> +++ b/drivers/net/ethernet/intel/e1000e/netdev.c
> >>> @@ -5691,14 +5691,17 @@ static int e1000_runtime_suspend(struct device *dev)
> >>>          struct pci_dev *pdev = to_pci_dev(dev);
> >>>          struct net_device *netdev = pci_get_drvdata(pdev);
> >>>          struct e1000_adapter *adapter = netdev_priv(netdev);
> >>> +       int retval;
> >>> +       bool wake;
> >>>
> >>> -       if (e1000e_pm_ready(adapter)) {
> >>> -               bool wake;
> >>> +       if (!e1000e_pm_ready(adapter))
> >>> +               return 0;
> >>>
> >>> -               __e1000_shutdown(pdev,&wake, true);
> >>> -       }
> >>> +       retval = __e1000_shutdown(pdev,&wake, true);
> >>> +       if (!retval)
> >>> +               e1000_power_off(pdev, true, wake);
> >>>
> >>> -       return 0;
> >>> +       return retval;
> >>>   }
> >>>
> >>>   static int e1000_idle(struct device *dev)
> >>>
> >
> > I'd like the changelog to say what the bug is and how it is being fixed in
> > general terms.
> 
> Ok, my bad.
> 
> Problem: ethernet device does not work (no carrier signal).
> Right after boot it goes to runtime-suspend and never wake up.
> 
> Original code (before your commit) calls pci_prepare_to_sleep() and it
> calls pci_enable_wake() and switches device to one of D3 state.

The original code in what function?

> It seems redundant, because pci_pm_runtime_suspend() do the same thing
> after calling ->runtime_suspend callback. Or rather it did it before commit
> 42eca2302146fed51335b95128e949ee6f54478f ("PCI: Don't touch card regs after
> runtime suspend D3") and third patch aimed fix this damage.
> 
> More over seems like calling pci_enable_wake() from e1000e isn't enough for my case,
> because my enthernet cannot wakeup from runtime-suspend without third patch.

Which third patch?

> Seems like it's because pci_enable_wake() and pci_finish_runtime_suspend()
> calls different pratform-pm callbacks -- platform_pci_run_wake() /
> platform_pci_sleep_wake().

That's correct, for historical reasons.  We'll need to merge these things, but
for now the are separate (because of the way ACPI handles system suspend and
runtime PM).

Thanks,
Rafael


-- 
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
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