On Friday, August 03, 2012, Huang Ying wrote: > This patch fixes the following bug: > > http://marc.info/?l=linux-pci&m=134329923124234&w=2 > > The root cause of the bug is as follow. > > If a device is not bound with the corresponding driver, the device > runtime PM will be disabled and the device will be put into suspended > state. So that, the bridge/PCIe port connected to it may be put into > suspended and low power state. When do probing for the device later, > because the bridge/PCIe port connected to it is in low power state, > the IO access to device may fail. > > To solve the issue, the bridge/PCIe port connected to the device is > put into active state before probing. > > Reported-by: Bjorn Mork <bjorn@xxxxxxx> > Signed-off-by: Huang Ying <ying.huang@xxxxxxxxx> Reviewed-by: Rafael J. Wysocki <rjw@xxxxxxx> > --- > drivers/pci/pci-driver.c | 6 ++++++ > 1 file changed, 6 insertions(+) > > --- a/drivers/pci/pci-driver.c > +++ b/drivers/pci/pci-driver.c > @@ -280,8 +280,12 @@ static long local_pci_probe(void *_ddi) > { > struct drv_dev_and_id *ddi = _ddi; > struct device *dev = &ddi->dev->dev; > + struct device *parent = dev->parent; > int rc; > > + /* The parent bridge must be in active state when probing */ > + if (parent) > + pm_runtime_get_sync(parent); > /* Unbound PCI devices are always set to disabled and suspended. > * During probe, the device is set to enabled and active and the > * usage count is incremented. If the driver supports runtime PM, > @@ -298,6 +302,8 @@ static long local_pci_probe(void *_ddi) > pm_runtime_set_suspended(dev); > pm_runtime_put_noidle(dev); > } > + if (parent) > + pm_runtime_put(parent); > return rc; > } > > > -- 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
