On Fri, 21 Feb 2014, Dan Williams wrote: > > Round 2: add usb 3 hcd > > > > usb_add_hcd() // secondary usb3 hcd > > hcd->self.root_hub = usb_alloc_dev() > > hcd->driver->reset(hcd) -> xhci_gen_setup() > > if(primary_hcd) // false > > .. > > else > > pm_runtime_put_noidle(hcd->self.controller) // -1 usage, * > > register_root_hub(hcd) -> usb_new_device(usb_dev) > > pm_runtime_set_active(&udev->dev); > > pm_runtime_get_noresume(&udev->dev); > > pm_runtime_use_autosuspend(&udev->dev); > > pm_runtime_enable(&udev->dev); > > ... > > pm_runtime_put_sync_autosuspend(&udev->dev); // ok to trigger would > > trigger xhci_suspend if all usages were 0. > > > > *) unnecessary to trigger any suspend as we're just about to register the > > usb3 roothub. but we need to decrement the usage counter. > > Right, but I assume you'd want to hold the reference until after the > hub is registered, otherwise there's still a chance we suspend right > before register. So I'm saying hold the reference until the > registration process takes its own. To be really safe about it, you should call pm_runtime_get_noresume at the start of xhci_pci_probe, and pm_runtime_put_noidle at the end (as well as in the error return pathways). Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
