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SubjectRe: [PATCH v3] PCI / PM: Always check PME wakeup capability for runtime wakeup support
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> On Apr 13, 2018, at 3:29 PM, Rafael J. Wysocki <rjw@rjwysocki.net> wrote:
>
> On Friday, April 13, 2018 8:58:11 AM CEST Kai Heng Feng wrote:
>> Hi Bjorn and Rafael,
>>
>>> On Apr 1, 2018, at 12:40 AM, Kai-Heng Feng <kai.heng.feng@canonical.com>
>>> wrote:
>>>
>>> USB controller ASM1042 stops working after commit de3ef1eb1cd0 ("PM /
>>> core: Drop run_wake flag from struct dev_pm_info").
>>>
>>> The device in question is not power managed by platform firmware,
>>> furthermore, it only supports PME# from D3cold:
>>> Capabilities: [78] Power Management version 3
>>> Flags: PMEClk- DSI- D1- D2- AuxCurrent=55mA PME(D0-,D1-,D2-,D3hot-,D3cold+)
>>> Status: D0 NoSoftRst+ PME-Enable- DSel=0 DScale=0 PME-
>>>
>>> Before commit de3ef1eb1cd0, the device never gets runtime suspended.
>>> After that commit, the device gets runtime suspended, so it does not
>>> respond to any PME#.
>>>
>>> usb_hcd_pci_probe() mandatorily calls device_wakeup_enable(), hence
>>> device_can_wakeup() in pci_dev_run_wake() always returns true.
>>>
>>> So pci_dev_run_wake() needs to check PME wakeup capability as its first
>>> condition.
>>>
>>> In addition, change wakeup flag passed to pci_target_state() from false
>>> to true, because we want to find the deepest state that the device can
>>> still generate PME#.
>>>
>>> Fixes: de3ef1eb1cd0 ("PM / core: Drop run_wake flag from struct
>>> dev_pm_info")
>>> Cc: stable@vger.kernel.org # 4.13+
>>> Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
>>> ---
>>> v3: State the reason why the wakeup flag gets changed.
>>>
>>> v2: Explicitly check dev->pme_support.
>>
>> If this patch is good enough, I am hoping it can get merged in v4.17.
>
> OK
>
> Bjorn, if you want to take this:
>
> Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
>
> Otherwise please let me know and I'll queue it up.

Hi, Rafael,
Can this patch be merged into your tree?

Kai-Heng

>
>
>>> drivers/pci/pci.c | 8 ++++----
>>> 1 file changed, 4 insertions(+), 4 deletions(-)
>>>
>>> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
>>> index f6a4dd10d9b0..52821a21fc07 100644
>>> --- a/drivers/pci/pci.c
>>> +++ b/drivers/pci/pci.c
>>> @@ -2125,16 +2125,16 @@ bool pci_dev_run_wake(struct pci_dev *dev)
>>> {
>>> struct pci_bus *bus = dev->bus;
>>>
>>> - if (device_can_wakeup(&dev->dev))
>>> - return true;
>>> -
>>> if (!dev->pme_support)
>>> return false;
>>>
>>> /* PME-capable in principle, but not from the target power state */
>>> - if (!pci_pme_capable(dev, pci_target_state(dev, false)))
>>> + if (!pci_pme_capable(dev, pci_target_state(dev, true)))
>>> return false;
>>>
>>> + if (device_can_wakeup(&dev->dev))
>>> + return true;
>>> +
>>> while (bus->parent) {
>>> struct pci_dev *bridge = bus->self;

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