Hi Roy, Thank you for reviewing my patch. > > Wouldn't the parent glue dev already resume before resuming the child dwc3? > No, in the following case, the parent device will not be reviewed before resuming the child device. Taking the 'imx8mp-dwc3' driver as an example. Step 1.usb disconnect trigger: the child device dwc3 enter runtime suspend state firstly, followed by the parent device imx8mp-dwc3 enters runtime suspend flow:dwc3_runtime_suspend->dwc3_imx8mp_runtime_suspend Step2.system deep trigger:consistent with the runtime suspend flow, child enters pm suspend and followed by parent flow: dwc3_pm_suspend->dwc3_imx8mp_pm_suspend Step3: After dwc3_pm_suspend, and before dwc3_imx8mp_pm_suspend, a task terminated the system suspend process . The system will resume from the checkpoint, and resume devices in the suspended state in the reverse of pm suspend, but excluding the parent device imx8mp-dwc3 since it did not execute the suspend process. > >Why would 'runtime PM trying to activate child device xxx.dwc3 but parent is not active' happen in the first place? > Following the above analysis, dwc3_resume calls pm_runtime_set_active(dev), it checks the parent.power->runtime_status is not RPM_ACTIVE and outputs the error log. > >What is the glue driver that's being used here? Knowing what's being done in the glue driver pm callbacks >would help in understanding the issue. > Refer to the driver 'dwc3-imx8mp.c' please, maybe you could help me find a better solution. Thanks, ryan Roy Luo <royluo@xxxxxxxxxx> 于2025年8月27日周三 02:38写道： > > On Tue, Aug 26, 2025 at 8:12 AM Ryan Zhou <ryanzhou54@xxxxxxxxx> wrote: > > > > Issue description: > > The parent device dwc3_glue has runtime PM enabled and is in the > > runtime suspended state. The system enters the deep sleep process > > but is interrupted by another task. When resuming dwc3, > > console outputs the log 'runtime PM trying to activate child device > > xxx.dwc3 but parent is not active'. > > > > Wouldn't the parent glue dev already resume before resuming the child dwc3? > Why would 'runtime PM trying to activate child device xxx.dwc3 but parent is > not active' happen in the first place? > What is the glue driver that's being used here? Knowing what's being done in > the glue driver pm callbacks would help in understanding the issue. > > Regards, > Roy
