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

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Message-ID: <51076CEE.8050706@openvz.org>
Date:	Tue, 29 Jan 2013 10:32:14 +0400
From:	Konstantin Khlebnikov <khlebnikov@...nvz.org>
To:	"Rafael J. Wysocki" <rjw@...k.pl>
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

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.

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.
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().

All this looks messy and I don't know how it should work.

If you prefer to minimize changes -- I can test how it would work without
first (this) patch. Probably fine.

>
> Thanks,
> Rafael
>
>

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