On Thu, Jun 2, 2016 at 10:17 AM, Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx> 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@xxxxxxxxxxxxx> > Signed-off-by: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> > --- > 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@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
