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RE: Problems debugging multithreaded program wirh gdbserver via ser ial

To: "Daniel Jacobowitz" <dan@debian.org>
Subject: RE: Problems debugging multithreaded program wirh gdbserver via ser ial port
From: "Yoni Rabinovitch" <Yoni.Rabinovich@Teledata-Networks.com>
Date: Mon, 8 Nov 2004 17:53:40 +0200
Cc: <linux-mips@linux-mips.org>
Original-recipient: rfc822;linux-mips@linux-mips.org
Sender: linux-mips-bounce@linux-mips.org
Thread-index: AcTFoLZYcvhp9WyQTwe7MqGi0WP+WwABXtcg
Thread-topic: Problems debugging multithreaded program wirh gdbserver via se rial port
>> 1)  If I try to run the program from gdbserver (i.e. gdbserver /dev/ttyS0 
>> wlsd), I get "readchar: Input/output error" messages,
>> and nothing works. See attached file gdb_fail.
>> What is going on here ?

>It sounds like your serial port is messed up.

What exactly do you mean by "messed up" ? 
minicom seems to work OK. What do I need to check ?

>> 3) If I repeat the scenario described in 2), but with "set debug remote 1", 
>> it seems to work somewhat faster
>> (e.g. bt takes about 1 minute to complete).
>> I am seeing alot of "Packet instead of Ack, ignoring it" messages.
>> See attached file gdb_trace_debug.
>> What do these messages mean ? 

>Try "set debug serial 1" in addition - it's very verbose but maybe it
> will tell you what the "packet" is.

Running with "set debug serial 1" gives me the following:

In the gdb session,I see lots of the following messages:
[O][K][#][9][a][$]Packet instead of Ack, ignoring it

Simultaneously, in the gdbserver session (via minicom) I see:
+$OK#9a

Then, in the gdb session, I see lots of the following:
[2][7][9][c][3][9][0][c][#][0][4][$]Packet instead of Ack, ignoring it

at which point, the gdbserver (minicom) session now proudly shows:
+$OK#9a$279c390c#04

See the attached file (gdb_trace_serial).

Why am I seeing stuff printed at the gdbserver (minicom) session ? Is this an 
indication that
something is wrong with the serial port, and if so, what ? What is the 
significance of the 
messages gdb thinks are "Packet instead of Ack", which also seem to get printed 
out (once) in the
gdbserver session ?

Thanks !!

Attachment: gdb_trace_serial
Description: gdb_trace_serial

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