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authorMika Westerberg <mika.westerberg@linux.intel.com>2016-06-02 11:17:13 +0300
committerBjorn Helgaas <bhelgaas@google.com>2016-06-13 14:57:58 -0500
commitd963f6512e15fb2c0a9e9770078e2206f55c2f7a (patch)
tree7171b4bff0089b092976e7b0672db144e018854b
parent9d26d3a8f1b0c442339a235f9508bdad8af91043 (diff)
downloadlinux-d963f6512e15fb2c0a9e9770078e2206f55c2f7a.tar.gz
PCI: Power on bridges before scanning new devices
When a PCI device is removed through sysfs interface, the upstream bridge (PCIe port) can be runtime suspended if it was the last device on that bus. Now, if the bridge is in D3 we cannot find devices below the bridge anymore. For example following fails to find the removed device again: # echo 1 > /sys/bus/pci/devices/0000:00:01.0/0000:01:00.0/remove # echo 1 > /sys/bus/pci/devices/0000:00:01.0/rescan Where 0000:00:01.0 is the bridge device. In order to be able to rescan devices below the bridge add pm_runtime_get_sync()/pm_runtime_put() calls to pci_scan_bridge(). This should keep bridges powered on while their children devices are being scanned. Reported-by: Peter Wu <peter@lekensteyn.nl> Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
-rw-r--r--drivers/pci/probe.c9
1 files changed, 9 insertions, 0 deletions
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 8e3ef720997d..11a802daf242 100644
--- 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);