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Re: Ctrl-C interrupt problem.
- To: Fabrice_Gautier at sdesigns dot com
- Subject: Re: Ctrl-C interrupt problem.
- From: Mark Salter <msalter at redhat dot com>
- Date: Thu, 16 Nov 2000 08:25:08 -0500
- CC: gdb at sources dot redhat dot com, ecos-discuss at sourceware dot cygnus dot com
- References: <B1F6452C89AFD411AE0800A0CC734C23015020@EMAIL1>
>>>>> 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