PCI PM: Introduce device flag wakeup_prepared

Introduce a new PCI device flag, wakeup_prepared, to prevent PCI
wake-up preparation code from being executed twice in a row for the
same device and for the same purpose.

Reviewed-by: Matthew Garrett <mjg59@srcf.ucam.org>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

2 files changed, 9 insertions, 0 deletions

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 84a6d6d30c5a..dcdfb2212ca3 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -1225,6 +1225,10 @@ int pci_enable_wake(struct pci_dev *dev, pci_power_t state, bool enable)
         if (enable && !device_may_wakeup(&dev->dev))
                 return -EINVAL;
 
+        /* Don't do the same thing twice in a row for one device. */
+        if (!!enable == !!dev->wakeup_prepared)
+                return 0;
+
         /*
          * According to "PCI System Architecture" 4th ed. by Tom Shanley & Don
          * Anderson we should be doing PME# wake enable followed by ACPI wake
@@ -1241,9 +1245,12 @@ int pci_enable_wake(struct pci_dev *dev, pci_power_t state, bool enable)
                 error = platform_pci_sleep_wake(dev, true);
                 if (ret)
                         ret = error;
+                if (!ret)
+                        dev->wakeup_prepared = true;
         } else {
                 platform_pci_sleep_wake(dev, false);
                 pci_pme_active(dev, false);
+                dev->wakeup_prepared = false;
         }
 
         return ret;
@@ -1365,6 +1372,7 @@ void pci_pm_init(struct pci_dev *dev)
         int pm;
         u16 pmc;
 
+        dev->wakeup_prepared = false;
         dev->pm_cap = 0;
 
         /* find PCI PM capability in list */
diff --git a/include/linux/pci.h b/include/linux/pci.h
index d80ed872a3c4..f5c7cd343e56 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -241,6 +241,7 @@ struct pci_dev {
         unsigned int    d1_support:1;   /* Low power state D1 is supported */
         unsigned int    d2_support:1;   /* Low power state D2 is supported */
         unsigned int    no_d1d2:1;      /* Only allow D0 and D3 */
+        unsigned int    wakeup_prepared:1;
 
 #ifdef CONFIG_PCIEASPM
         struct pcie_link_state  *link_state;    /* ASPM link state. */