PCI: Power on bridges before scanning new devices

[deliverable/linux.git] / drivers / pci / probe.c

diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 8e3ef720997dfba2858c4dae77b2a0651f678c2d..11a802daf242fa5d81a2c11ca10b8786cdbf403d 100644 (file)
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -16,6 +16,7 @@
 #include <linux/aer.h>
 #include <linux/acpi.h>
 #include <linux/irqdomain.h>
+#include <linux/pm_runtime.h>
 #include "pci.h"
 
 #define CARDBUS_LATENCY_TIMER  176     /* secondary latency timer */
@@ -832,6 +833,12 @@ int pci_scan_bridge(struct pci_bus *bus, struct pci_dev *dev, int max, int pass)
        u8 primary, secondary, subordinate;
        int broken = 0;
 
+       /*
+        * Make sure the bridge is powered on to be able to access config
+        * space of devices below it.
+        */
+       pm_runtime_get_sync(&dev->dev);
+
        pci_read_config_dword(dev, PCI_PRIMARY_BUS, &buses);
        primary = buses & 0xFF;
        secondary = (buses >> 8) & 0xFF;
@@ -1012,6 +1019,8 @@ int pci_scan_bridge(struct pci_bus *bus, struct pci_dev *dev, int max, int pass)
 out:
        pci_write_config_word(dev, PCI_BRIDGE_CONTROL, bctl);
 
+       pm_runtime_put(&dev->dev);
+
        return max;
 }
 EXPORT_SYMBOL(pci_scan_bridge);