PCI/PM: Do not generate wakeup event when runtime resuming device

When a PCI bridge is runtime resumed from D3cold, we resume any downstream
devices as well.  Previously, we also generated a wakeup event for each
device even though this is not a wakeup signal 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_resume_bus(), which generates a wakeup event and increases
wakeup_count.

Since this is not a real wakeup event, remove the call to
pci_wakeup_event() from pci_resume_one().

[bhelgaas: reorder, commit log]
Link: https://lore.kernel.org/r/20201125090733.77782-1-mika.westerberg@linux.intel.com
Reported-by: Utkarsh Patel <utkarsh.h.patel@intel.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 664aada..0102cc9 100644 (file)
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -1176,7 +1176,6 @@ EXPORT_SYMBOL_GPL(pci_platform_power_transition);
 
 static int pci_resume_one(struct pci_dev *pci_dev, void *ign)
 {
-       pci_wakeup_event(pci_dev);
        pm_request_resume(&pci_dev->dev);
        return 0;
 }