On Thursday 27 May 2010, Alan Stern wrote: > On Wed, 26 May 2010, Rafael J. Wysocki wrote: > > > On Wednesday 26 May 2010, Alan Stern wrote: > > > Rafael: > > > > > > I've been updating the patch Matthew Garrett posted last November, > > > adding runtime PM methods for PCI USB controllers. Overall the > > > situation is now easier, since the rest of the USB subsystem has been > > > converted over to the runtime PM framework. And it even seems to work! > > > > > > But there is one problem. The device driver needs to know, during its > > > pm_suspend callback, whether or not wakeup should be enabled. (Or more > > > accurately, the pm_suspend callback needs to fail if wakeup isn't going > > > to be available.) > > > > The driver can check that by calling pci_dev_run_wake() which returns false > > if there's no wakeup support for the device. > > Ah, okay, thanks. > > > However, that's not enough on > > some broken machines where some signal pins are simply not connected to the > > system core logic (as a result the PCI core thinks that wakeup is supported, > > but in fact it doesn't work due to the broken hardware - yes, there are > > machines like this in the wild, Matthew has one). > > We don't have to worry about that. If the hardware is broken and the > kernel doesn't realize it, the user will just have to tell it not to > allow runtime suspend for those devices. Yup. That's why we keep the PCI devices runtime PM in the "forbidden" state until user space changes that. Rafael -- 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
