Re: [BUG REPORT] usb: dwc3: Failed to link at superspeed in device mode

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Hi

Le mer. 10 oct. 2018 à 09:41, Felipe Balbi
<felipe.balbi@xxxxxxxxxxxxxxx> a écrit :
>
> first of all, thanks for following the documentation when reporting a
> bug, much appreciated.

That's the least I can do. Thanks for take into account my issue.

> Thomas JOURDAN <thomas.jourdan@xxxxxxxxx> writes:
> > On the UP2 board, it is not possible in device mode to get the USB3.0
> > OTG port working at superspeed. It is unclear yet if it is a bug in
> > the Linux DWC3 driver or the board itself.
> >
> > I have tried many cables, different host computers (Windows or Linux),
> > and the connection always links at hi-speed. In host mode, it works
> > fine at super speed. I tried many kernels, from upboard official one
> > to latest RC version ans the problem persists.
>
> So, it doesn't work with UP's original kernel either? Then I'm pretty
> sure either the board doesn't support super speed on the micro-b
> connector, or the board is faulty.

I have tested on 4 different boards and all exposes the same issue.
The micro-b USB connector is the USB3.0 OTG port, and super speed
works fine only in host mode. In parallel I will try to have a look at
the hardware level to see if there is anything I can do to improve the
signal quality.

> > DCFG = 0x004e0814
>
> maximum speed is set to super speed
>
> > [   74.055170] g_ether gadget: high-speed config #2: RNDIS
>
> but it enumerates in high speed.

Yes and that's also what reports the controller (DSTS = 0x00839fa8)

> From your trace.txt, I don't see the early enumeration phase, so I can't
> comment one what happened during that time. Care to rerun this so that
> we have early enumeration? I need to see a Reset Event on the trace as
> that's the first event when you first plug your usb cable.

I don't know why it isn't there because I plugged the cable *after* I
enabled the tracing. So I ran it a second time and despite the traces
are smaller, there seem to be what you expect (messages for U0 state
?) Also I can enable the debug messages for the USB gadget layer if
needed.




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