| Message ID | 1464855435-32960-4-git-send-email-mika.westerberg@linux.intel.com |
|---|---|
| State | Accepted |
| Headers | show |
On Thu, Jun 2, 2016 at 10:17 AM, Mika Westerberg <mika.westerberg@linux.intel.com> wrote: > 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> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> > --- > drivers/pci/probe.c | 9 +++++++++ > 1 file changed, 9 insertions(+) > > 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); > -- -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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);
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> --- drivers/pci/probe.c | 9 +++++++++ 1 file changed, 9 insertions(+)