bug#30505: marionette/virtio-console issues lead to test failures

[ludo@gnu.org (Ludovic Courtès)]

Hello,

Danny Milosavljevic <dannym@scratchpost.org> skribis:

>>I hadn’t noticed this is now part of ‘%base-services’.  It would be nice
> if it were enabled on ARM only.  Thoughts?
>
> Why?  It's not ARM-specific and there are people using headless x86 servers
> posting on the mailing list :)
>
> It's only enabled when you specify a serial port as console on the Linux
> command line - that's not going to happen accidentially.
>
> And once Linux uses the console for its messages it's nice to also have a
> login process running in the end - otherwise it's kinda annoying having
> only a read-only line when you sit right in front of the machine.

Oh OK, got it, that makes sense.  :-)

> On Mon, 19 Feb 2018 16:54:44 +0100
> ludo@gnu.org (Ludovic Courtès) wrote:
>
>> Commenting out (display "\x1b%G" (fdes->outport fd)) in (gnu services
>> base) appear to solve the problem.  It seems that it used to affect just
>> the terminal behind FD and now somehow broadcasts to all existing
>> terminals?
>
> It was a bad idea to do the "\x1b%G" in the first place.

Because it’s redundant with IUTF8?

> There's a Linux kernel command-line parameter "vt.default_utf8" which
> is set to true anyway.  In that case the iflag IUTF8 is set automatically
> by Linux drivers/tty/vt/vt.c and the driver also does the same as "\x1b%G"
> does in that case.
>
> So what do these things in (gnu services base) accomplish?  Sounds like
> they change nothing.
>
> Maybe that was only done in later Linux kernels? I checked 3.4.103, it did that
> already.

This ‘unicode-start’ procedure is essentially a port of the
‘unicode_start’ script from ‘kbd’.  I suppose the justification is to
make sure we’re using UTF-8 input regardless of what the kernel defaults
or command-line options are.

Thoughts?

Ludo’.