Re: Remote target behind console server

[Quality Quorum <qqi@theworld.com>]

On Thu, 4 Jul 2002, KONG, Gangfeng wrote:

> At 12:33 AM 7/4/2002 -0400, Quality Quorum wrote:
>
>
> >On Wed, 3 Jul 2002, KONG, Gangfeng wrote:
> >
> > >
> > > > >
> > > > > Hi,
> > > > >
> > > > > I start the gdb stub on the target by:
> > > > >          gdbstart -s 38400 -t /dev/ttyS0
> > > > > and start the gdb on the development box by:
> > > > >          gdb vmlinux
> > > > >          gdb)
> > > > >          gdb) set remotebaud 38400
> > > > >          gdb) target remote my-server-ipaddr:port  #note, the port
> > I put
> > > > > here is the serial port# on the server,
> > > > >                                                  #not L4 port, correct?
> > > >
> > > >No, you have to use telnet port here.
> > >
> > > Hi,
> > >
> > > normally, I use the command:
> > >          telent server-ipaddr 2001
> > > to access its port 1. (2002 for port 2, 2003 for port 3 ...)
> > >
> > > It looks like console server already map its L4 port into serial port.
> >
> >I suppose that L4 means port 4 on the server and /dev/ttyS0 on the target
> >then you have to use 'target server-ipaddr 2004'.
>
> In fact, L4 port, I mean Layer 4 (transport layer) port. Sorry for the
> confusion.
> I am very sure I was assigned at port 1. And I use 'telnet server-ipaddr 2001'
> to access the target console normally.,
>
>
>
> >If L4 means something else, then use another port.
> >
> >
> >How to debug a connection:
> >
> >1. Make sure that terminal server is properly configured and the
> >    cable is good:  connect port 4 on the terminal server to the some known
> >    working target, e.g. standar UNIX serial port, do 'telnet server-ip
> >    2004' and type stuff on console and check responses.
> >
> >2. Make sure that gdb stub is workin properly: connect port 4 on the
> >    terminal server to debug port on the targe, start gdb stub, again do
> >    'telnet server-ip 2004' and make sure that by hitting return you
> >    cause gdb to send you properly formed packets.
> >
> >3. Start gdb and do 'target remote server-ip:2004' I would be very
> >    surprised if it does not work at the point.
> >
>
> In order to check the whole system, I did install a kgdb stub of linux on my
> laptop, so that I can move it around. What I have done are:
> 1. enable the /dev/ttyS0 in /etc/inittab, then I can login through serial port
>      the check whether it works. I connect it to the port 1 of my console
> server,
>      then, I remotely login into it by 'telnet server-ipaddr 2001'. Works!
>      SO:
>          - target serial port works
>          - console server works
> 2. I move the laptop target close to my development box, and I use serial cable
>      to connect them directly. I start the stub on target by 'gdbstart -s
> 38400 -t
>      /dev/ttyS0'. And then start the gdb on the development box. Now I can use
>      gdb to debug my target box as expected.
>      SO:
>          - the stub on target is ok
>          - the gdb on the development box is ok


I suppose that you are using null-modem cable at the point.


> 3. Now I move the laptop target back to the console server and connect the port
>      1 to its serial port and start the stub by 'gdbstart -s 38400 -t
> /dev/ttyS0', and
>      go the development box to start the gdb and try to access the target
> box by
>      'target remote server-ipaddr:2001'.
>      But it fails......
>
> I don't know what's wrong.

I suppose port configuration or wrong cable or wrong baud rate, I
suppose you have to use stright cable here and in many cases authobaud
feature does not work with gdb stub.

Anyway, connect you rtarget to the terminal server, start gdb stub, do
'telnet serverip 2001' and try to figure out what is going wrong until
you see '$...#yy in response to pressing ENTER.


>
> Thanks
> GF
>
>

Thanks,

Aleksey