On 22-01-10 23:07:48, Mathias Nyman wrote: > On 10.1.2022 14.33, Peter Chen wrote: > > On 22-01-07 15:58:26, Frank Li wrote: > >> Mathias Nyman > >> > >> Recently we found a crash at xhci_disable_hub_port_wake when system suspend if enable remote wake up. > >> > >> Basial flow is. > >> > >> 1. run time suspend call xhci_suspend, xhci parent devices gate the clock. > >> 2. echo mem >/sys/power/state, system _device_suspend call xhci_suspend > >> 3. xhci_suspend call xhci_disable_hub_port_wake, which access register, but clock already gated by run time pm. > >> > >> Why find this issue now, that is because previous power domain driver will call run time resume before it. But the below commit remove it. > >> > >> c1df456d0f06eb9275c1cd4c66548fc5738ea428 > >> Author: Ulf Hansson ulf.hansson@xxxxxxxxxx > >> Date: Thu Mar 4 20:28:43 2021 +0100 > >> > >> PM: domains: Don't runtime resume devices at genpd_prepare() > >> > >> > >> > >> According to HCD_FLAG_HW_ACCESSIBLE logic, xhci should not access hardware when second time call xhci_suspend without call xhci_resume. > >> > >> xhci_disable_hub_port_wake(xhci, &xhci->usb3_rhub, do_wakeup); > >> xhci_disable_hub_port_wake(xhci, &xhci->usb2_rhub, do_wakeup); > >> > >> if (!HCD_HW_ACCESSIBLE(hcd)) > >> return 0; > >> > >> ..... > >> clear_bit(HCD_FLAG_HW_ACCESSIBLE, &hcd->flags); > >> clear_bit(HCD_FLAG_HW_ACCESSIBLE, &xhci->shared_hcd->flags); > >> > >> I am not sure if it is safe to move xhci_disable_hub_port_wake after HCD_HW_ACCESSIBLE check, Or need add additional run_time_resume before it. > > We probably need to runtime resume first in case we need to adjust the wakeup settings > > > > > Frank, I prefer adding runtime resume at xhci-plat.c like below, let's see what > > Mathias says. > > > > > > diff --git a/drivers/usb/host/xhci-plat.c b/drivers/usb/host/xhci-plat.c > > index c1edcc9b13ce..47a5a10381a7 100644 > > --- a/drivers/usb/host/xhci-plat.c > > +++ b/drivers/usb/host/xhci-plat.c > > @@ -440,6 +440,9 @@ static int __maybe_unused xhci_plat_suspend(struct device *dev) > > ret = xhci_priv_suspend_quirk(hcd); > > if (ret) > > return ret; > > + > > + if (pm_runtime_suspended(dev)) > > + pm_runtime_resume(dev); > > /* > > * xhci_suspend() needs `do_wakeup` to know whether host is allowed > > * to do wakeup during suspend. > > > > Yes, looks like a solution to me. > Just checked that driver-api/pm/devices.rst also suggest calling > pm_runtime_resume() in ->suspend callback if device needs to adjust wakeup > capabilities. > > Frank Li, does this work for you? > > Peter, if we now make sure xhci host is not runtime suspended at system suspend, > does it mean that the !HCD_HW_ACCESSIBLE(hcd) check you added to xhci_suspend() > is no longer needed? Yes, it is no longer needed if xhci host is not runtime suspended. -- Thanks, Peter Chen
