Re: Ctrl-C interrupt problem.

[Mark Salter <msalter at redhat dot com>]

>>>>> Fabrice Gautier writes:

> [eCos and RedBoot guys, I think this may concern you 
>  its about a ctrl-C problem which only happen when debugging via ethernet.
>  full story in the gdb list archives ]

> I Got it! 
> Well, i hope....

> And it make sens why it only happens with TCP...

> The problem is that when gdb send the continue packet to the target, it wait
> for the target to send the '+' Ack. During this time the SIGINT handler is
> not set.

> My guess is that RedBoot intedn to send it BUT (tata) the ethernet driver
> just wait to have a full packet before really sending! So this happen when a
> O packet is sent.

> So i guess the only thing needed in RedBoot is to add a "flush" somewhere.
> I'm not sure at what level, but i'll look at it tomorrow if nobody does it
> before.

> Thanks

> -- 
> Fabrice Gautier
> fabrice_gautier@sdesigns.com 


Yes, it appears that redboot only flushes the output stream when
it sees the end of a packet. This causes the problem you see.

Look at .../redboot/current/src/net/net_io.c:net_io_putc().

A quick workaround would be to also flush if a '+' is seen. This
has a downside as it may severely impact download speeds, but at
least it is functionally correct. YMMV.

This needs to be fixed with a flush of the output stream prior
to continuing or stepping the target. Its not clear to me right
now how this can be done.

--Mark