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. > 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. -- 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
