On Thu, Sep 11, 2025 at 09:51:50PM +0800, ryan zhou wrote: > Hi Xu， > > Xu Yang <xu.yang_2@xxxxxxx> 于2025年9月11日周四 18:58写道： > > > > Hi Ryan, > > > > On Thu, Sep 11, 2025 at 01:32:47AM +0000, Thinh Nguyen wrote: > > > On Wed, Sep 10, 2025, Ryan Zhou wrote: > > > > Issue description:During the wake-up sequence, if the system invokes > > > > dwc3->resume and detects that the parent device of dwc3 is in a > > > > runtime suspend state, the system will generate an error: runtime PM > > > > trying to activate child device xxx.dwc3 but parent is not active. > > > > > > > > Solution:At the dwc3->resume entry point, if the dwc3 controller > > > > is detected in a suspended state, the function shall return > > > > immediately without executing any further operations. > > > > > > > > Signed-off-by: Ryan Zhou <ryanzhou54@xxxxxxxxx> > > > > --- > > > > drivers/usb/dwc3/core.c | 3 +++ > > > > 1 file changed, 3 insertions(+) > > > > > > > > diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c > > > > index 370fc524a468..06a6f8a67129 100644 > > > > --- a/drivers/usb/dwc3/core.c > > > > +++ b/drivers/usb/dwc3/core.c > > > > @@ -2687,6 +2687,9 @@ int dwc3_pm_resume(struct dwc3 *dwc) > > > > struct device *dev = dwc->dev; > > > > int ret = 0; > > > > > > > > + if (pm_runtime_suspended(dev)) > > > > + return ret; > > > > + > > > > > > Is this a documented behavior where the device should remain runtime > > > suspend on system resume? I feel that that this should be configurable > > > by the user or defined the PM core. I don't think we should change > > > default behavior here just to workaround the issue that we're facing. > > > > > > What if the user wants to keep the old behavior and resume up the device > > > on system resume? > > > > What about resume the device firstly if it's already runtime suspended when > > call dwc3_pm_suspend(). Therefor, the old behavior can be kept and the issue > > can be avoided. > > Originally, I also believed that forcing the device to remain active > before PM suspend > was necessary. However, this approach has two drawbacks: > 1. It prolongs the system's sleep transition time. > 2. Worse, if a USB insertion wakes the system during enumeration, > the system may > re-enter sleep before the USB device is fully recognized. Can you provide more detail about point 2? When is the USB device inserted? Is the re-enter behavior caused by pm_runtime_resume()? Thanks, Xu Yang > > > diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c > > index 370fc524a468..1b8dbb260017 100644 > > --- a/drivers/usb/dwc3/core.c > > +++ b/drivers/usb/dwc3/core.c > > @@ -2672,6 +2672,9 @@ int dwc3_pm_suspend(struct dwc3 *dwc) > > struct device *dev = dwc->dev; > > int ret; > > > > + if (pm_runtime_suspended(dev)) > > + pm_runtime_resume(dev); > > + > > ret = dwc3_suspend_common(dwc, PMSG_SUSPEND); > > if (ret) > > return ret;
