Sergio,

I see your concerns and I agree to everything you mentioned.
I don't have equipment (and knowledge) to check if USB hardware works 100%
correct (I'm using STM32 mc).
This is VCP host written by me and as long as it get connected to internet
it works stable.
Problem I described is only happen during connection phase and it's
floating problem - only happen in about 30% cases, means in 70% connection
attempts everything connects just fine and after that works (receiving and
transmitting megabytes of data) for many hours without any issues.
I hoped there could be an easy fix somewhere in lwipopts, but this seems
not the case.
I will look deeper in bytes that travels over the USB and see if I can find
anything interesting.

-----
Regards,
Gennady
mob. +7 985 8181210

On Mon, Feb 29, 2016 at 7:48 PM, Sergio R. Caprile <[email protected]>
wrote:

> Looks like we've got someone else to blame...
>
> So you have a modem vía USB... you don't have PPP over serial, you have
> PPP over something over USB.
>
> What is it, VCP ? with host drivers written by... (you ?) that you know
> works OK because... (?) And, btw, the USB hardware is OK ? (USB
> transfers are CRC "protected" but...)
>
> I guess you should see why there are two packets when there is a bad
> fcs. It is the only moment when it happens. Looks like "someone" got
> interrupted and didn't finish a transfer, lost state, and then resumed
> with some missing bytes in the middle, causing an fcs failure.
> Check your USB statistics, maybe transfer errors are firing something
> unexpected.
>
>
> _______________________________________________
> lwip-users mailing list
> [email protected]
> https://lists.nongnu.org/mailman/listinfo/lwip-users
>
_______________________________________________
lwip-users mailing list
[email protected]
https://lists.nongnu.org/mailman/listinfo/lwip-users

Reply via email to