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

[Bjorn Helgaas <bhelgaas@google.com>]

On Thu, Mar 28, 2013 at 6:57 AM, Rafael J. Wysocki <rjw@sisk.pl> wrote:
> Hi Bjorn,
>
> I wonder what you think about the patch below?

Seems fine to me (I'm trusting your and Matthew's judgment here since
I don't know much about it).  Why don't you resend it with Matthew's
ack and the appropriate stable tags, and I'll put it in.  If you have
a URL for a bugzilla or mailing list report of the original problem,
that would be good, too.  It'd be nice if users and distros could
match problem reports with this solution, but I can't tell what the
user-visible issue was.  I assume that Sarah tested this (or somebody
else reproduced the problem and tested the fix)?

> On Saturday, March 23, 2013 03:33:03 PM Rafael J. Wysocki wrote:
>> From: Rafael J. Wysocki <rafael.j.wysocki@intel.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@linux.intel.com>
>> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
>> ---
>>  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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> --
> I speak only for myself.
> Rafael J. Wysocki, Intel Open Source Technology Center.