On Fri, Jul 13, 2018 at 04:35:33PM -0400, Alan Stern wrote:
> On Fri, 13 Jul 2018, Bin Liu wrote:
>
> > Hi,
> >
> > I got a report saying that when overcurrent happens in one of the hub
> > downstream ports, USB_PORT_STAT_OVERCURRENT is not set in portstatus,
> > instead USB_PORT_STAT_C_OVERCURRENT is set in portchange, then the
> > overcurrent condition is not handled in hub_event().
> >
> > The following patch solves the issue.
> >
> > t a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
> > index 442be7f312f6..118557acc74b 100644
> > --- a/drivers/usb/core/hub.c
> > +++ b/drivers/usb/core/hub.c
> > @@ -1144,7 +1144,8 @@ static void hub_activate(struct usb_hub *hub, enum
> > hub_activation_type type)
> > * check for a new connection
> > */
> > if (udev || (portstatus & USB_PORT_STAT_CONNECTION)
> > ||
> > - (portstatus & USB_PORT_STAT_OVERCURRENT))
> > + (portstatus & USB_PORT_STAT_OVERCURRENT) ||
> > + (portchange & USB_PORT_STAT_C_OVERCURRENT))
> > set_bit(port1, hub->change_bits);
> >
> > } else if (portstatus & USB_PORT_STAT_ENABLE) {
>
> Please also update the immediately preceding comment.
Sure.
>
> > The usb2.0 spec section 11.12.5 states
> > "If a hub has per-port power switching and per-port current limiting, an
> > over-current on one port may still cause the power on another port to
> > fall below specific minimums. In this case, the affected port is placed
> > in the Power-Off state and C_PORT_OVER_CURRENT is set for the port, but
> > PORT_OVER_CURRENT is not set."
> >
> > So is the patch above a proper fix? or something else might be missing?
>
> It certainly seems like a reasonable thing to do. If you say it fixes
> the problem, we can add it in.
Will send the patch.
Thanks,
-Bin.
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