Bug#857808: debian-installer: Garbage on terminal with default TERM setting over serial console

[Samuel Thibault <sthibault@debian.org>]

Samuel Thibault, on dim. 19 mars 2017 18:12:46 +0100, wrote:
> Samuel Thibault, on dim. 19 mars 2017 17:25:36 +0100, wrote:
> > John Paul Adrian Glaubitz, on mer. 15 mars 2017 12:05:56 +0100, wrote:
> > > Basically, it works when booting with TERM_TYPE=linux (no colors)
> > > or TERM=ansi (setting TERM=linux produces garbage as well). It
> > > does not work when not setting TERM or TERM_TYPE at all or when
> > > setting TERM to vt102.
> > 
> > Well, what terminal are you actually using on the serial port?
> 
> Are you actually using a terminal software between the serial output and
> your Konsole?  If not, it is not surprising bogus things happen, see the
> manual, you can e.g. use screen in between to convert from vt102 to your
> Konsole desires.
> 
> More precisely, the issue here seems to be with ACS, which is spuriously
> getting set (or perhaps rather missing getting cleared) by your terminal
> here.

And I'm wondering whether that could come from some \0 characters added
by ncurses to "respect" the baud speed.

Would you be able to tinker your test images to inject

stty speed 0

before screen gets started? e.g. in lib/debian-installer.d/S70menu

(it's a crude hack to make it emit zero \0 characters, just to check
whether those are the culprits)

Samuel