On 17 May 2016 at 16:00, Felipe Balbi <balbi@xxxxxxxxxx> wrote: > > Hi > > Baolin Wang <baolin.wang@xxxxxxxxxx> writes: >> Hi Felipe, >> >> On 13 May 2016 at 20:46, Felipe Balbi <balbi@xxxxxxxxxx> wrote: >>> >>> Hi, >>> >>> Baolin Wang <baolin.wang@xxxxxxxxxx> writes: >>>>>>> why does it need restart? Why is dwc3 powered off? Who powers it off? >>>>>> >>>>>> Because when the dwc3 Vbus is off (no cable pluging in now), >>>>>> especially for some mobile device, the system need to power off the >>>>>> dwc3 to save power in this situation. >>>>> >>>>> but dwc3 doesn't do this by itself, so who's doing it? >>>> >>>> Yes, the dwc3 clock is controlled by the Soc system, so the Soc system >>>> can disable the dwc3 clock when there is no cable plugging in. >>> >>> understood. >>> >>>>>>> This looks like a *really* bad power management implementation. Do you >>>>>>> have hibernation enabled? Do you have Clock gating enabled? Which dwc3 >>>>>>> version are you using? How was it configured? >>>>>> >>>>>> This is not hibernation, we want to power off the dwc3 to save power >>>>>> when no cable plugging in. Yes, we have clock gating, at this >>>>>> situation we will disable the clock and shutdown the phy to save >>>>>> power. For mobile device, most time no cable plugging in, so we need >>>>>> to think about the power consuming. How do you think this requirement? >>>>> >>>>> Well, seems like you're missing *proper* runtime PM. I've been meaning >>>>> to work on it for weeks, but I still have a few other things to do >>>>> before I get to that. In any case, we don't need to do what you did >>>>> here. There are better ways. >>>> >>>> Make sense. >>> >>> cool, if you wanna work on it, let me know and I can give some details >>> of what I have in mind. >> >> Could you explain details to me, and I wanna continue to optimize the >> power management things. Thanks. > > I have it half-way done. Have a look at my dwc3-fix-suspend branch on > k.org. I haven't sent because I'm not getting a PME event. Can you test > on your end and let me know what happens? OK. I try to test on my platform to see what will happen. > > Note that if cable is disconnected, we will drop RUN/STOP bit. On > runtime_resume, we will restart the controller from scratch (skipping > memory allocations, of course) > > -- > balbi -- Baolin.wang Best Regards -- 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
