[tbot] How to debug acquire_linux

Harald Seiler hws at denx.de
Fri Nov 23 08:48:19 UTC 2018

Hi Stefano,

On Thu, 2018-11-22 at 23:47 +0100, Stefano Babic wrote:
> Hi,
> On 22/11/18 19:24, Stefano Babic wrote:
> > Hi,
> > 
> > I have a board that cannot be got in linux. It looks like that
> > tbot.acquire_linux() hangs forever (can I set a tiimeout ?)
> > 
> > I ran a testcase that works fine for another board - I guess that the
> > issue is due to the fact that this board has a lot of output in part
> > caused by systemd and in part due to kernel messages that are printed to
> > the console. When I start the testcase, tbot remains in <board>-linux. I
> > can understand that board is up and works because software activates
> > some relays, but it is not recognized by tbot.
> > 
> > The weird thing is that "interactive_linux" works. How can I debug this
> > ? Or do we have to block kernel messages to the console via kernel
> > parameter ?
> > 
> I have some more details. The not working board has "bash" as shell and
> TERM is set to "xterm". Running tbot with -vvv, after "root" as user,
> the bord answers with some terminal control characters. It looks like
> that tbot gets confused. If I replace "bash" with "busybox", it works.

Hmm, can you send me the output of -vvv? The only cases I know don't
work is when something is sent after the password prompt or once the
shell comes up ...

You could try defining `login_wait`[1] in your BoardLinuxMachine
and see if that helps ...

> The second not working case seems if the board prints some data on the
> console after the login propt is sent. This is the case when a daemon
> has the stdout set to the console. Also in this case, it seems that tbot
> gets confused.

Yes, this is an open issue:


I don't know how we best handle this case ... Do you have any ideas?

> Bye,
> Stefano

[1] https://rahix.de/tbot/module-board.html#tbot.machine.board.LinuxWithUBootMachine

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