diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index e98c8104297b..710c8a29be0d 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -1007,6 +1007,18 @@ static int __pci_enable_device_flags(struct pci_dev *dev, int err; int i, bars = 0; + /* + * Power state could be unknown at this point, either due to a fresh + * boot or a device removal call. So get the current power state + * so that things like MSI message writing will behave as expected + * (e.g. if the device really is in D0 at enable time). + */ + if (dev->pm_cap) { + u16 pmcsr; + pci_read_config_word(dev, dev->pm_cap + PCI_PM_CTRL, &pmcsr); + dev->current_state = (pmcsr & PCI_PM_CTRL_STATE_MASK); + } + if (atomic_add_return(1, &dev->enable_cnt) > 1) return 0; /* already enabled */