Oddity with ugen

[Hans Petter Selasky]

On 05/18/16 17:53, Karl Denninger wrote:
> This is being seen on a Pi2 / 11-Current.
>
> I'm reasonably sure that the Pi2 itself and the base USB code is ok,
> however, because there is another USB device also in use by the same
> software (it emulates a serial port and so attaches on the serial
> driver; it exposes itself as a /dev/cua.... device) which has never
> exhibited repeated frames although it too talks using interrupt mode,
> and also has a packet style of communication, so if it was doing the
> same sort of thing my code would have been yelling about it,
> particularly since that other device also generates sequence numbers on
> the packets for use by the software in implementing a callback stack
> (this one doesn't.)

Hi,

Is this reproducable on a PC w/ EHCI/OHCI/UHCI/XHCI ?

Can you check the USB speed of the two different devices? LOW/HIGH/FULL

The RPi2 drives most of the USB controller in software, which might 
influence some of the timing. Further there is quirk for USB interrupt 
endpoints in the DWC OTG driver, but I'm not sure if that is the cause 
of the problem.

What is the exact time between these spurious packets as seen by usbdump?

--HPS