Merge tag 'pm-5.13-rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

Pull power management fix from Rafael Wysocki:
 "Revert a recent PCI power management commit that causes initialization
  issues to appear on some systems"

* tag 'pm-5.13-rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  Revert "PCI: PM: Do not read power state in pci_enable_device_flags()"

1 files changed, 13 insertions, 3 deletions

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index b717680377a9..8d4ebe095d0c 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -1900,11 +1900,21 @@ static int pci_enable_device_flags(struct pci_dev *dev, unsigned long flags)
 	int err;
 	int i, bars = 0;
 
-	if (atomic_inc_return(&dev->enable_cnt) > 1) {
-		pci_update_current_state(dev, dev->current_state);
-		return 0;		/* already enabled */
+	/*
+	 * 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_inc_return(&dev->enable_cnt) > 1)
+		return 0;		/* already enabled */
+
 	bridge = pci_upstream_bridge(dev);
 	if (bridge)
 		pci_enable_bridge(bridge);