Hi, On 7/21/2017 12:28 PM, Baolin Wang wrote: > For some mobile devices with strict power management, we also want to > suspend the host when the slave was detached for power saving. Thus > adding the host suspend/resume functions to support this requirement. USB/PM core already takes care of suspending root-HUB/XHCI when no device connected. > > We will issue the pm_suspend_ignore_children() for the dwc3 device, > since we will resume the child device (xHCI device) in runtime resume > callback (dwc3_host_resume()) of dwc3 device, now the dwc3 device's > runtime state is not RPM_ACTIVE, which will block to resume its > child device (xHCI device). Add ignore children flag can avoid this > situation. This defeats the basic purpose of runtime PM. Without ignore_children once USB bus is suspended, dwc3 gets suspended and then dwc3 glue device. Only requirement I see from the patch is to resume XHCI/root-hub on dwc3 resume. I am sure there must be other way to deal with that e.g. doing same from glue driver by using a wq or use pm_request_resume() > > Signed-off-by: Baolin Wang <baolin.wang@xxxxxxxxxx> > --- > drivers/usb/dwc3/core.c | 26 +++++++++++++++++++++++++- > drivers/usb/dwc3/core.h | 7 +++++++ > drivers/usb/dwc3/host.c | 15 +++++++++++++++ > 3 files changed, 47 insertions(+), 1 deletion(-) > > diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c > index 326b302..2be7ddc 100644 > --- a/drivers/usb/dwc3/core.c > +++ b/drivers/usb/dwc3/core.c > @@ -1193,6 +1193,7 @@ static int dwc3_probe(struct platform_device *pdev) > pm_runtime_use_autosuspend(dev); > pm_runtime_set_autosuspend_delay(dev, DWC3_DEFAULT_AUTOSUSPEND_DELAY); > pm_runtime_enable(dev); > + pm_suspend_ignore_children(dev, true); > ret = pm_runtime_get_sync(dev); > if (ret < 0) > goto err1; > @@ -1292,15 +1293,27 @@ static int dwc3_remove(struct platform_device *pdev) > static int dwc3_suspend_common(struct dwc3 *dwc) What is the trigger for runtime suspend now that you have ignore_children set. > { > unsigned long flags; > + int ret; > > switch (dwc->dr_mode) { > case USB_DR_MODE_PERIPHERAL: > + spin_lock_irqsave(&dwc->lock, flags); > + dwc3_gadget_suspend(dwc); > + spin_unlock_irqrestore(&dwc->lock, flags); > + break; > case USB_DR_MODE_OTG: > + ret = dwc3_host_suspend(dwc); With DRD/OTG, if current mode is device and dwc3->xhci won't be valid. You can refer to the patch that I pushed to address this. > + if (ret) > + return ret; > + > spin_lock_irqsave(&dwc->lock, flags); > dwc3_gadget_suspend(dwc); > spin_unlock_irqrestore(&dwc->lock, flags); > break; > case USB_DR_MODE_HOST: > + ret = dwc3_host_suspend(dwc); > + if (ret) > + return ret; > default: > /* do nothing */ > break; > @@ -1322,12 +1335,23 @@ static int dwc3_resume_common(struct dwc3 *dwc) > > switch (dwc->dr_mode) { > case USB_DR_MODE_PERIPHERAL: > + spin_lock_irqsave(&dwc->lock, flags); > + dwc3_gadget_resume(dwc); > + spin_unlock_irqrestore(&dwc->lock, flags); > + break; > case USB_DR_MODE_OTG: > + ret = dwc3_host_resume(dwc); > + if (ret) > + return ret; > + > spin_lock_irqsave(&dwc->lock, flags); > dwc3_gadget_resume(dwc); > spin_unlock_irqrestore(&dwc->lock, flags); > - /* FALLTHROUGH */ > + break; > case USB_DR_MODE_HOST: > + ret = dwc3_host_resume(dwc); > + if (ret) > + return ret; > default: > /* do nothing */ > break; > diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h > index ea910ac..9b5a4eb 100644 > --- a/drivers/usb/dwc3/core.h > +++ b/drivers/usb/dwc3/core.h > @@ -1193,11 +1193,18 @@ static inline bool dwc3_is_usb31(struct dwc3 *dwc) > #if IS_ENABLED(CONFIG_USB_DWC3_HOST) || IS_ENABLED(CONFIG_USB_DWC3_DUAL_ROLE) > int dwc3_host_init(struct dwc3 *dwc); > void dwc3_host_exit(struct dwc3 *dwc); > +int dwc3_host_suspend(struct dwc3 *dwc); > +int dwc3_host_resume(struct dwc3 *dwc); > #else > static inline int dwc3_host_init(struct dwc3 *dwc) > { return 0; } > static inline void dwc3_host_exit(struct dwc3 *dwc) > { } > + > +static inline int dwc3_host_suspend(struct dwc3 *dwc) > +{ return 0; } > +static inline int dwc3_host_resume(struct dwc3 *dwc) > +{ return 0; } > #endif > > #if IS_ENABLED(CONFIG_USB_DWC3_GADGET) || IS_ENABLED(CONFIG_USB_DWC3_DUAL_ROLE) > diff --git a/drivers/usb/dwc3/host.c b/drivers/usb/dwc3/host.c > index 76f0b0d..3fa4414 100644 > --- a/drivers/usb/dwc3/host.c > +++ b/drivers/usb/dwc3/host.c > @@ -16,6 +16,7 @@ > */ > > #include <linux/platform_device.h> > +#include <linux/pm_runtime.h> > > #include "core.h" > > @@ -151,3 +152,17 @@ void dwc3_host_exit(struct dwc3 *dwc) > dev_name(dwc->dev)); > platform_device_unregister(dwc->xhci); > } > + > +int dwc3_host_suspend(struct dwc3 *dwc) > +{ > + struct device *xhci = &dwc->xhci->dev; > + > + return pm_runtime_suspend(xhci); If ignore_children is not marked then xhci would indeed be suspended. > +} > + > +int dwc3_host_resume(struct dwc3 *dwc) > +{ > + struct device *xhci = &dwc->xhci->dev; > + > + return pm_runtime_resume(xhci); Other than what I pushed in my patch - ("usb: dwc3: Don't reinitialize core during host bus-suspend/resume") Just performing pm_request_resume or handling same in dwc3 glue driver should be sufficient. Also, what is trigger for runtime_resume for your platform? -- 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