On Thu, 13 Feb 2014, Peter Chen wrote:
> > > - If you have a usb bus analyzer, please check if the GET_DESCRPTOR sends
> > > out successfully.
> > > (Most probably, I don't think it sends out)
> >
> > I've attached a screen cap of the USB capture. At the to in red is the
> > "SETUP txn" that fails in u-boot (shows Timed Out). Below on the second
> > capture, the Get Descriptor succeeds to the same device, but this time from
> > Linux.
Have you compared the capture result with the same thing on a Linux PC?
Can you make the capture data available publicly?
> > Should the analyzer show the IN/OUT portion of the first get-descriptor or
> > does that only show up when the device responds? I'm no too familiar with
> > USB protocol.
>
> Using plain text to send email next time please, you can upload capture at
> some
> place.
>
> For GET_DESCRIPTOR:
>
> setup stage:
> host sends setup token
> host sends data (8 bytes here)
> device sends IN for response
Not exactly.
Host sends SETUP packet, which consists of a SETUP token
followed by 8 bytes of data and a 2-byte CRC.
Device sends ACK for response.
> data stage:
> host sends IN token
> device sends data (8 bytes here)
> host sends OUT for response
Host sends IN token packet.
Device sends DATA0 or DATA1 packet containing data and CRC.
Host sends ACK for response.
> status stage:
> host sends OUT
> host sends 0-byte data
> device sends IN for response
Host sends OUT token packet.
Host sends 0-length DATA1 packet.
Device sends ACK for response.
> Since I can't see device IN response for setup stage from your capture
> log, but I assume the device is ok.
If the SETUP packet is invalid, the device won't respond to it. If the
SETUP packet is valid, the device MUST respond with ACK.
> So your problem may is the host does not send out IN token for data
> stage, please check the function qh_urb_transaction at u-boot
> (if the name is the same with linux) to see if the qtd for data
> stage is setup correctly.
Alan Stern
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