On Thu, Sep 11, 2025, ryan zhou wrote: > Thinh Nguyen <Thinh.Nguyen@xxxxxxxxxxxx> 于2025年9月11日周四 09:32写道： > > > > 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. > > No documentation was found, but modifying the runtime suspend state > after wakeup from sleep seems unnecessary if the device was already > in runtime suspend before sleep. > > > What if the user wants to keep the old behavior and resume up the device > > on system resume? > For USB devices, RPM resume should be initiated by plug/unplug events, > not PM resume when the device is physically disconnected. > Why not? This resume will also apply for host right? The host can be woken up by a remote-wake signal that triggers a pm_resume. The user may expect the host to resume on pm_resume. We may implement device hibernation in the future where RPM resume is relevant more than just plug/unplug events. BR, Thinh
