On Tue, 2016-12-27 at 10:20 -0500, Alan Stern wrote:
> On Tue, 27 Dec 2016, Oliver Neukum wrote:
>
> > On Thu, 2016-12-22 at 17:44 -0500, Alan Stern wrote:
> > > I don't see how this patch fixes anything. Unless I'm mistaken, it
> > > just avoids the problem by preventing the system from issuing the
> > > command that provokes the error, rather than really fixing the
> > > underlying error.
> >
> > Please clarify. If a reset leads to a disconnect, isn't that
> > exactly what we want?
>
> I didn't express myself clearly enough. Yes, if a reset leads to a
> disconnect then avoiding the reset will avoid problems.
Good. Then we need to clarify whether the device was physically
disconnected when the logs were taken.
> But the _real_ error here is that xhci-hcd says "ERROR Transfer event
> for disabled endpoint or incorrect stream ring" when the disconnect
> occurs during reset. That shouldn't happen, no matter what quirks the
> device has. It indicates a bug either in uas or in xhci-hcd.
True. I am afraid that there necessarily is a window for resetting a
disconnected device. But the check you proposed is better.
however, I'd like to encapsulate that together with a test for
logical disconnect. Uas is unlikely to be the only driver that has
this issue.
Regards
Oliver
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