On Fri, Jun 14, 2013 at 9:31 AM, Chao Xie <xiechao.mail@xxxxxxxxx> wrote: > On Thu, Jun 13, 2013 at 11:08 PM, Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> wrote: >> On Thu, 13 Jun 2013, Chao Xie wrote: >> >>> >> These operations sound generic enough to be done at HCD layer, no? So no need to >>> >> replicate the same stuff in ohci, ehci, xhci, etc. >>> > >>> > The HCD layer handles suspend and resume only for PCI host controllers. >>> > Not for other types. >>> > >>> > I don't know if the acquire/start and stop/release parts can be moved >>> > into the USB core. Maybe they can. >>> > >>> > Alan Stern >>> > >>> hi >>> The following is my understanding. >>> I think for PHY initialization and shutdown part, it is generic for >>> other parts. >>> PHY initialization need to be called before hc_driver->reset is called. >>> I think it can be added at usb_add_hcd. >>> For PHY shutdown, it can be added at usb_remove_hcd. >> >> Yes, that should work. >> > Fine, i can add a patch for that. My usb phy patches are pending on it. > >>> For suspend/resume, i do not know how to add it. For our EHCI driver, >>> when system goes to deep idle states, we just directly shutdown the >>> hcd and initialize it again when the system goes back. >> >> You shut down the host controller? Then how does it detect wakeup >> events? And how does it know if a device was disconnected while the >> power was off? >> > Hi > I think maybe my suspend/resume is not same as what you think. > The suspend/resume i mean is the peripharal sub system suspend/resume > states. When SOC enter this low power mode, > the clock to usb, power to usb are all shut down. > When the controller is shut down, i think that usb_remove_hcd will > help to remove all the attached devices. > We do not rely on usb host controller to wake up the whole sub system. > If a device is disconnected while the power was off, when the host > controller is powered again, it will do initialization again, and all > the attached devices are susposed be removed already. > > hi I am sorry that i unerstand it wrong. I checked with the code in our 3.4 git. we really did a lot of things when suspend/resume, and at that point the patch for ehci_resume and ehci_suspend are not added. i think the driver can make use of ehci_resume/ehci_suspend. For PHY, we have to initialize it and shutdown it when do suspend/resume. Our PHY do not have any suspend states. I suppose these phy operation have to be handled by each ehci driver owner only, or you think it can be handled at ehci-hce level?. >> 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
