On Wed, Nov 25, 2020 at 12:07:32PM +0300, Mika Westerberg wrote: > When a PCI bridge is runtime resumed from D3cold the underlying bus is > walked and the attached devices are runtime resumed as well. However, in > addition to that we also generate a wakeup event for these devices even > though this actually is not a real wakeup event coming from the > hardware. > > Normally this does not cause problems but when combined with > /sys/power/wakeup_count like using the steps below: > > # count=$(cat /sys/power/wakeup_count) > # echo $count > /sys/power/wakeup_count > # echo mem > /sys/power/state > > The system suspend cycle might fail at this point if a PCI bridge that > was runtime suspended (D3cold) was runtime resumed for any reason. The > runtime resume calls pci_wakeup_bus() and that generates wakeup event > increasing wakeup_count. > > Since this is not a real wakeup event we can prevent the above from > happening by removing the call to pci_wakeup_event() in > pci_wakeup_bus(). > > Reported-by: Utkarsh Patel <utkarsh.h.patel@xxxxxxxxx> > Signed-off-by: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx> > Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> I reversed the order of these since I think it's more obvious that pci_wakeup_event() doesn't fit in pci_resume_one() and applied both to pci/pm for v5.11, thanks! > --- > Previous version can be found here: > > https://www.spinics.net/lists/linux-pci/msg101083.html > > Changes from the previous version: > > - Split the patch in two. The second patch only does the rename. > - Tried to improve the commit message a bit > - Added Rafael's reviewed-by tag > > drivers/pci/pci.c | 1 - > 1 file changed, 1 deletion(-) > > diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c > index e578d34095e9..6f7b33998fbe 100644 > --- a/drivers/pci/pci.c > +++ b/drivers/pci/pci.c > @@ -1181,7 +1181,6 @@ EXPORT_SYMBOL_GPL(pci_platform_power_transition); > */ > static int pci_wakeup(struct pci_dev *pci_dev, void *ign) > { > - pci_wakeup_event(pci_dev); > pm_request_resume(&pci_dev->dev); > return 0; > } > -- > 2.29.2 >
