[PATCH] usb: core: hub: fix race condition about TRSMRCY of resume

[Chunfeng Yun]

On Tue, 2021-05-11 at 12:39 -0400, Alan Stern wrote:
> On Tue, May 11, 2021 at 06:15:22PM +0800, Chunfeng Yun wrote:
> > This may happen if the port becomes resume status exactly
> > when usb_port_resume() gets port status, it still need provide
> > a TRSMCRY time before access the device.
> > 
> > Reported-by: Tianping Fang <tianping.fang at mediatek.com>
> > Signed-off-by: Chunfeng Yun <chunfeng.yun at mediatek.com>
> 
> This should also say:
> 
> CC: <stable at vger.kernel.org>

OK, thanks

> 
> > ---
> >  drivers/usb/core/hub.c | 6 +++---
> >  1 file changed, 3 insertions(+), 3 deletions(-)
> > 
> > diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
> > index b2bc4b7c4289..fc7d6cdacf16 100644
> > --- a/drivers/usb/core/hub.c
> > +++ b/drivers/usb/core/hub.c
> > @@ -3642,9 +3642,6 @@ int usb_port_resume(struct usb_device *udev, pm_message_t msg)
> >  		 * sequence.
> >  		 */
> >  		status = hub_port_status(hub, port1, &portstatus, &portchange);
> > -
> > -		/* TRSMRCY = 10 msec */
> > -		msleep(10);
> >  	}
> >  
> >   SuspendCleared:
> > @@ -3659,6 +3656,9 @@ int usb_port_resume(struct usb_device *udev, pm_message_t msg)
> >  				usb_clear_port_feature(hub->hdev, port1,
> >  						USB_PORT_FEAT_C_SUSPEND);
> >  		}
> > +
> > +		/* TRSMRCY = 10 msec */
> > +		msleep(10);
> >  	}
> >  
> >  	if (udev->persist_enabled)
> 
> Acked-by: Alan Stern <stern at rowland.harvard.edu>