+linux-usb On Thu, Nov 18, 2021 at 03:21:54PM +0530, Rohith Kollalsi wrote: > Hi Mathias, > > This mail is regarding your upstream change in xhci file. There is a > potential issue with your change which can cause noc error due to unclocked > access. > > Consider a case where a headset is connected to device and nothing is > playing. As nothing is playing, usb bus wouldn't be active which leads to > run time suspend ( i think this feature is not present upstream) as a part > of which xhci_suspend will be called. Now all the clocks are also switched > off. Now again when pm_suspend occurs due to disconnect, then again > xhci_suspend occurs, but now registers can be accessed with clocks off > leading to unclocked access. Can you please consider below change to prevent > unclocked access. > > > diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c > > index 2728027..aaf212d 100644 > > --- a/drivers/usb/host/xhci.c > > +++ b/drivers/usb/host/xhci.c > > @@ -1013,13 +1013,13 @@ int xhci_suspend(struct xhci_hcd *xhci, bool > do_wakeup) > > xhci->shared_hcd->state != HC_STATE_SUSPENDED) > > return -EINVAL; > > + if (!HCD_HW_ACCESSIBLE(hcd)) ---> this will prevent unclocked access > when xhci_suspend occurs during second time during pm_suspend > > + return 0; > > + > > /* Clear root port wake on bits if wakeup not allowed. */ > > 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; > > - > > xhci_dbc_suspend(xhci); > > > Thanks, > > Rohith
