On 7/13/2017 11:33 AM, Baolin Wang wrote: > On 12 July 2017 at 16:58, Manu Gautam <mgautam@xxxxxxxxxxxxxx> wrote: >> >> On 7/12/2017 2:06 PM, Baolin Wang wrote: >>> Hi, >>> >>> On 12 July 2017 at 15:25, Manu Gautam <mgautam@xxxxxxxxxxxxxx> wrote: >>>> >>>> On 7/12/2017 12:19 PM, Baolin Wang wrote: >>>>> Hi, >>>>> >>>>> On 3 July 2017 at 19:25, Manu Gautam <mgautam@xxxxxxxxxxxxxx> wrote: >>>>>> Driver powers-off PHYs and reinitializes DWC3 core and gadget on >>>>>> resume. While this works fine for gadget mode but in host >>>>>> mode there is not re-initialization of host stack. Also, resetting >>>>>> bus as part of bus_suspend/resume is not correct which could affect >>>>>> (or disconnect) connected devices. >>>>>> Fix this by not reinitializing core on suspend/resume in host mode >>>>>> for HOST only and OTG/drd configurations. >>>>> But for some mobile devices, they also need suspend/resume in host >>>>> mode which will power off dwc3 controller in glue layer. If we remove >>>>> dwc3_core_init() for host mode, I am afraid it can not work well in >>>>> host mode after resuming dwc3. >>>> Can you point me to a glue driver doing that? >>> Yes, now there are no glue driver doing that, but for many vendor >>> trees they will do that. (Our platform will power off dwc3 when >>> suspending dwc3, but have not upstreamed yet) >> >> Fine, but glue driver still need to take care of re-initialization on resume >> with current design. > Yes. > >>>> If dwc3 is powered off on suspend then Xhci level initialization also >>>> needed >>>> after >>>> performing dwc3_core_init on resume which is currently not present. So >>>> this >>>> seems >>>> to me broken anyway. >>> Since we've add runtime PM for xhci-plat driver [1], which means we >>> can runtime suspend/resume xhci device from dwc3 [2]. >>> [1] https://www.spinics.net/lists/linux-usb/msg156077.html >>> [2] https://patchwork.kernel.org/patch/9471869/ >> >> Sure. We can discuss this patch once you re-submit. >> One concern I have with the patch is marking ignore_children for dwc3 and as >> part of >> dwc3 suspend/resume invoking > Suppose we will suspend xhci device as dwc3's child, but now dwc3 > device is not suspend yet, which will block to suspend xhci device. > Thus we should set ignore children flag to remove the parent > dependency. I may not have understood the issue. In any case children must be suspended first. Example sequence is: external hub/device (if any) suspend -> root hub -> xhci -> dwc3 core -> dwc3 glue. xhci device's runtime/pm suspend should happen before dwc3 gets suspended. >> runtime pm on xhci. Ideally pm core should handle it seamlessly i.e. >> suspending dwc3 >> once xhci gets suspended and pm_stay_awake/relax can be used to block >> pm_suspend >> until runtime suspend of glue driver happens. >> >>> But [2] has not applied yet now, I will try to upstream it again. Then >>> we can suspend xhci device--> suspend dwc3 host---> glue layer can >>> power off, and it is similar when resuming in host mode. >> >> Do you see any issues with this patch? >> I am able to get runtime suspend/resume happening fine with XHCI on my >> platform. >> It involves runtime suspend/resume of USB HUB and dwc3 glue driver without >> any other >> change. > Great, I will try this patch again. > -- 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
