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authorMika Westerberg <mika.westerberg@linux.intel.com>2016-05-23 11:20:48 +0300
committerBjorn Helgaas <bhelgaas@google.com>2016-05-23 16:43:32 -0500
commitaf81f0fa638b13b6bc0ac2c815dd4acbfc02400b (patch)
tree2add8dfb2e52132d720e3cd07774c54f703d8d9f
parent9741a01c9f550d19c2e310e525aae9a09dd0c01c (diff)
downloadlinux-af81f0fa638b13b6bc0ac2c815dd4acbfc02400b.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>
-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 8004f67c57ec..15e77c92311e 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);