minicom bug and linux kernel 2.6.25.4

[Adam Lackorzynski]

Hi,

On Wed Jun 11, 2008 at 07:50:48 -0500, R.L. Horn wrote:
> On Tue, 10 Jun 2008, Adam Lackorzynski wrote:
> 
> > Thanks for your effort. I found my problem... I just used the wrong 
> > cable (uuups...). So when I try everything works now, without any 
> > modifications in minicom and on 2.6.25. So I can suspect something very 
> > special. On the other hand the standard PC stuff should all use the same 
> > serial driver, weird... So I suspect there's nothing strange in your 
> > dmesg about ttyS? (non-16550A type e.g.)
> 
> Nope.
> 
> I found a thread in the linux-kernel mailing list that seems to address 
> this, but which died without resolution.  Personally, I believe all the 
> speculation was way off.
> 
> Exactly what I'm seeing is this:
> 
>    Opening a serial device brings up DTR and RTS.
> 
>    Setting the baud rate to B0 clears DTR and RTS (as per SUS).
> 
>    Resetting the baud rate doesn't bring the control lines back up,
>    whereas it did under linux-2.6.24.*.  It looks like minicom may be
>    unique in its dependence on this behavior.

So I have tried to reproduce the above with a Courier connected via some
(random) USB-Serial converter, with 2.6.25.4. TR LED is off, starting
minicom, TR LED is on, setting baud rate to 0 (added 0 baud rate to make
this possible), TR LED is off, setting to 115200 (again), TR goes on.
(RS is always on.)

> So, for example, if I run "minicom -o" (thereby skipping the initial 
> m_dtrtoggle() call), DTR and RTS are high and everything works as 
> expected.

Hmm, your init-sequence? I have none mostly, maybe that makes a
difference.

> I'm going to try to revive the linux-kernel thread and, hopefully, come up 
> with something definitive.

Thanks, we'll see what Alan has to say.


Adam
-- 
Adam                 adam at os.inf.tu-dresden.de
  Lackorzynski         http://os.inf.tu-dresden.de/~adam/