On Tue, 8 Apr 2014, vichy wrote:

> > That's a different bit.  USB_PORT_FEAT_C_RESET isn't the same as
> > USB_PORT_FEAT_RESET.
> what I am curious is,
> if port reset bit will clear to 0 within 2ms, why we still need to
> clear_port_feature with USB_PORT_FEAT_C_RESET
> (clear Port reset )
> >
> >>         if (hub_is_superspeed(hub->hdev)) {
> >>             clear_port_feature(hub->hdev, port1,
> >>                     USB_PORT_FEAT_C_BH_PORT_RESET);
> >>             clear_port_feature(hub->hdev, port1,
> >>                     USB_PORT_FEAT_C_PORT_LINK_STATE);
> >>             clear_port_feature(hub->hdev, port1,
> >>                     USB_PORT_FEAT_C_CONNECTION);
> >>         }

Because if we leave these bits set, the hub will send messages on its 
interrupt endpoint telling us that these bits need to be cleared.

Alan Stern

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