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Re: Ctrl-C interrupt problem.
- To: Mark Salter <msalter at redhat dot com>
- Subject: Re: Ctrl-C interrupt problem.
- From: Fernando Nasser <fnasser at cygnus dot com>
- Date: Thu, 16 Nov 2000 13:47:32 +0000
- CC: Fabrice_Gautier at sdesigns dot com, gdb at sources dot redhat dot com, ecos-discuss at sourceware dot cygnus dot com
- Organization: Red Hat Canada Ltd. - Toronto
- References: <B1F6452C89AFD411AE0800A0CC734C23015020@EMAIL1> <200011161325.eAGDP8P09301@deneb.localdomain>
Nice catch Fabrice.
Congratulations on your persistence.
Fernando
Mark Salter wrote:
>
> >>>>> 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
--
Fernando Nasser
Red Hat Canada Ltd. E-Mail: fnasser@redhat.com
2323 Yonge Street, Suite #300
Toronto, Ontario M4P 2C9