diff --git a/drivers/pci/bus.c b/drivers/pci/bus.c
index 4383a36fd6ca..41e5c45e38b5 100644
--- a/drivers/pci/bus.c
+++ b/drivers/pci/bus.c
@@ -15,6 +15,7 @@
 #include <linux/of.h>
 #include <linux/of_platform.h>
 #include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
 #include <linux/proc_fs.h>
 #include <linux/slab.h>
 
@@ -379,6 +380,13 @@ void pci_bus_add_device(struct pci_dev *dev)
 		put_device(&pdev->dev);
 	}
 
+	/*
+	 * Enable runtime PM, which potentially allows the device to
+	 * suspend immediately, only after the PCI state has been
+	 * configured completely.
+	 */
+	pm_runtime_enable(&dev->dev);
+
 	if (!dn || of_device_is_available(dn))
 		pci_dev_allow_binding(dev);
 
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 10ea5e7f4b34..835efe729a62 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -1488,6 +1488,9 @@ static int pci_set_low_power_state(struct pci_dev *dev, pci_power_t state, bool
 	   || (state == PCI_D2 && !dev->d2_support))
 		return -EIO;
 
+	if (dev->current_state == state)
+		return 0;
+
 	pci_read_config_word(dev, dev->pm_cap + PCI_PM_CTRL, &pmcsr);
 	if (PCI_POSSIBLE_ERROR(pmcsr)) {
 		pci_err(dev, "Unable to change power state from %s to %s, device inaccessible\n",
@@ -3196,8 +3199,14 @@ void pci_pm_init(struct pci_dev *dev)
 poweron:
 	pci_pm_power_up_and_verify_state(dev);
 	pm_runtime_forbid(&dev->dev);
+
+	/*
+	 * Runtime PM will be enabled for the device when it has been fully
+	 * configured, but since its parent and suppliers may suspend in
+	 * the meantime, prevent them from doing so by changing the
+	 * device's runtime PM status to "active".
+	 */
 	pm_runtime_set_active(&dev->dev);
-	pm_runtime_enable(&dev->dev);
 }
 
 static unsigned long pci_ea_flags(struct pci_dev *dev, u8 prop)