On Wednesday, August 31, 2016 08:15:18 AM Lukas Wunner wrote: > We currently perform a mandatory runtime resume of all PCI devices on > ->shutdown. However it is pointless to wake devices only to immediately > power them down afterwards. (Or have the firmware reset them, in case > of a reboot.) > > It seems there are only two cases when a runtime resume is actually > necessary: If the driver has declared a ->shutdown callback or if kexec > is in progress. > > Constrain resume of a device to these cases and let it slumber > otherwise, thereby conserving energy and speeding up shutdown. > > Cc: Rafael J. Wysocki <rjw@xxxxxxxxxxxxx> > Signed-off-by: Lukas Wunner <lukas@xxxxxxxxx> > --- > drivers/pci/pci-driver.c | 5 +++++ > 1 file changed, 5 insertions(+) > > diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c > index fd4b9c4..09a4e56 100644 > --- a/drivers/pci/pci-driver.c > +++ b/drivers/pci/pci-driver.c > @@ -459,6 +459,11 @@ static void pci_device_shutdown(struct device *dev) > struct pci_dev *pci_dev = to_pci_dev(dev); > struct pci_driver *drv = pci_dev->driver; > > + /* Fast path for suspended devices */ > + if (pm_runtime_suspended(dev) && (!drv || !drv->shutdown) && > + !kexec_in_progress) What happens if runtime suspend or resume of the device happens here? > + return; > + > pm_runtime_resume(dev); > > if (drv && drv->shutdown) > Thanks, Rafael -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
