[Mageia-dev] musical session locations

[Colin Guthrie]

'Twas brillig, and Felix Miata at 04/02/13 21:56 did gyre and gimble:
>> I think that startx and init are deprecated in favour of proper systemd
>> commands now.
> 
> Init at shell prompt is shorthand/alias for insanely long non-memorable
> systemd replacements for telinit/init.

"init" still works for now. It likely will for as long as we have some
degree of runlevel mappings - I can't see these going away anytime soon
as there is no real need.

I still think "systemctl default" or "systemctl start graphical.target"
is semantically clearer and thus likely easier to remember than the
entirely abstract "init 5" which, although shorter, it's semantically
meaningless by itself. That said, with both you need some degree of
knowledge anyway and thus the net difference in terms of such things is
likely zero overall.

> Startx may be deprecated, but no one who's told me so has suggested
> what's supposed to replace it to get 2nd, 3rd & more X sessions going on
> :1, :2, etc.

It's a deprecated technique, but that doesn't mean it doesn't still
work. Nothing will specifically replace it, other than the functionality
already built into the Desktop Environments for many years where you can
do "Fast User Switching" or "Login as another User" which will
automatically start another X session on :1 or :2 as needed.

Logging in multiple times as the same user is something that's,
generally speaking, not officially supported by most of the DE's these
days - i.e. trying to login as yourself during "Fast user switch" will
often just switch you back to and unlock your original session.

>>> On current
>>> boot I used 3 on cmdline, logged in on tty2 & tty3, did startx on tty3,
>>> and found X is running on tty3. On exiting the X session I did init 5.
>>> That put KDM on tty1. On openSUSE & Fedora the problem is essentially
>>> the same, e.g.: https://bugzilla.novell.com/show_bug.cgi?id=768788
> 
>> I don't think this is grub2 related.
> 
> Of course it's not. It's fallout from incomplete migration from sysvinit
> to systemd. Systemd is designed to not do a significant number of things
> that sysvinit did do, so things are broken that haven't been modified to
> do what the functioning init system no longer does, or account for
> everything the replacement init system does differently.

Citation needed. What are these "significant number of things" that
sysvinit did?

>> Graphical desktop should default to tty1 now
> 
> I have predfined uses for ttys 1-6. 7, 8 & 9 are where my X sessions
> belong, not on 1 and random others making me guess each time what lives
> where. Tty1 especially needs not to be where X goes, because it's where
> in help forums everyone dealing with non-working X is told to login to
> do this and do that to troubleshoot.

Oh jeeze, this was discussed prior to Mageia 2. I'm really not going to
entertain such nonsense now. If you want it different, then fine - knock
yourself out, edit all the various things you need to edit (this
includes modifying multiple DM configurations and also editing the
default prefdm.service file to ensure it doesn't conflict with
getty at tty1.service and also (likely) statically starting
getty at tt{2,3,4,5,6}.service also if you want these pre-launched (thus
blocking any future X11 from being launched there.

It's your system, you can do what you want with it, but OOTB we will be
trying to provide a logical user experience that is not tied to some
historical, syntactically and logically irrelevant concept.

Things are far more complex than they used to be with multiple seats
being dynamically added and removed and DMs have to cope with a
multitude of different conditions. Things have to be reexamined and
rethought from time to time.


> More about what systemd doesn't do that init did. Initab reserved ttys
> 1-6 leaving 7+ free for X sessions. Systemd reserves none and doesn't
> even start a getty until switch to a tty is made.

Yup, that's the OOTB behaviour. Don't like it? Fine, you are free to
configure things that way:

sed 's/^\(Conflicts=\)/#\1/' /usr/lib/systemd/system/prefdm.service
>/etc/systemd/system/prefdm.service
systemctl --system daemon-reload
systemctl -f enable prefdm.service

# systemctl enable getty at tty{2,3,4,5,6}.service
# The above should be made to work, but it doesn't currently - patch pending
for tty in 2 3 4 5 6; do ln -s /usr/lib/systemd/system/getty at .service
/etc/systemd/system/getty.target.wants/getty at tty${tty}.service; done


Reconfigure your DM to start on tty7 and you're done.

That said, the whole VT concept is slowly dying anyway. Talks like this
at FOSDEM highlight this:
https://fosdem.org/2013/schedule/event/kmscon/

I'm afraid that if you want to keep such systems long into the future,
you better start keeping the current versions of distros around. The
only thing certain here, is change!

Col



-- 

Colin Guthrie
colin(at)mageia.org
http://colin.guthr.ie/

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