[SOLVED] Why the display manager kicks off first?

Horizon_Brave · 2015-11-12 17:52:59

Hi everyone,

I don't know about you all, but as I dig deeper into the murky jungles of the inner operating system, I think (for me) more questions arise than are answered. But some of the questions that I storm up I really hate to create multiple threads for, just for the mods to have to clean up, monitor and soon it'll just be forgotten. So I leave this idea up to the mods, but could this thread be kept around to post sort of quick, random questions, that really probably warrant a quick answer or just in general, not worth creating a completely new topic around. Anyway I (obviously) have a few quick picks lined up, so I can get this started:

1. In regards to the display/login manager, why is it up to this piece of software to kickstart everything else in the graphic env? Why is it responsible for starting x11? Isn't X responsible for doing the major foundational graphic creation? Shouldn't it be the very first gui application that's run? The display or login manager, to me, should be just a quick process that's started at boot, to authenticate and pass the user along. I was really surprised to find that ALL graphical processes orignate from the display manager... It just seems to me like Xorg is the bigger fish here, and that it should be the first and 'parent' of all the rest.

Last edited by Horizon_Brave (2015-11-13 19:57:12)

damo · 2015-11-12 18:07:00

Xorg, XFree86 and X11 are display servers, which create the graphical environment. This is where "ALL graphical processes originate".

The display manager (= login manager) is the first X program run by the system if the system (not the user) is starting X and allows you to log on to the local system, or network system. It doesn't "kickstart" the graphical environment - that has already happened.

Head_on_a_Stick · 2015-11-12 20:30:09

Horizon_Brave wrote:

I don't know about you all, but as I dig deeper into the murky jungles of the inner operating system, I think (for me) more questions arise than are answered. But some of the questions that I storm up I really hate to create multiple threads for, just for the mods to have to clean up, monitor and soon it'll just be forgotten. So I leave this idea up to the mods, but could this thread be kept around to post sort of quick, random questions, that really probably warrant a quick answer or just in general, not worth creating a completely new topic around.

I disagree.

To quote the great Carl Sagan:

There are naive questions, tedious questions, ill-phrased questions, questions put after inadequate self-criticism. But every question is a cry to understand the world. There is no such thing as a dumb question.

Please restrict yourself to a single thread per query.

This allows users with the same question to easily find the answer rather than it being buried away in a random thread.

Also, you don't need a display manager to start X.

ohnonot · 2015-11-12 20:41:02

Head_on_a_Stick wrote:

you don't need a display manager to start X.

https://wiki.archlinux.org/index.php/Xi … X_at_login
works on any distro (after you disable the login/display manager).

Head_on_a_Stick · 2015-11-12 21:01:18

ohnonot wrote:

https://wiki.archlinux.org/index.php/Xi … X_at_login
works on any distro (after you disable the login/display manager).

...as long as it uses systemd

The $XDG_VTNR variable is not set by sysvinit -- use this instead under sysvinit:

[[ -z "$DISPLAY" && $(tty) == /dev/tty1 ]] && startx

This will `startx` automatically after login to TTY1

johnraff · 2015-11-13 03:11:18

Yeh I think I agree with Head_on_a_Stick on this one. One-issue-per-thread makes it much easier for people who come afterwards to find the help they need.

OTOH I think sometimes there's a case for long megathreads when people are posting hints, links or short bits of code that won't trigger a discussion. Then you can just scroll down looking for the interesting stuff.

ohnonot · 2015-11-13 06:57:16

Head_on_a_Stick wrote:

The $XDG_VTNR variable is not set by sysvinit -- use this instead under sysvinit:
[[ -z "$DISPLAY" && $(tty) == /dev/tty1 ]] && startx

thanks for pointing this out.
there was even a bug in systemd recently (but long fixed now) that made me use the latter method...

KrunchTime · 2015-11-13 10:41:45

johnraff wrote:

Yeh I think I agree with Head_on_a_Stick on this one. One-issue-per-thread makes it much easier for people who come afterwards to find the help they need.

+1

tknomanzr · 2015-11-13 14:07:13

It is also important to consider the forum search capability, which works far better if there is something relating to your question in the thread title. I use search quite a bit when looking for something specific.

Horizon_Brave · 2015-11-13 16:45:52

Ok OK! I concede! Remove this thread then! 8.(

boot · 2015-11-13 17:12:10

LOL no it wil get it's own special place :-)

Head_on_a_Stick · 2015-11-13 19:45:51

Horizon_Brave wrote:

Remove this thread then! 8.(

No need for us to delete resolved problems

Please add "[SOLVED]" to the thread title for the benefit of others.

Horizon_Brave · 2015-11-13 19:55:19

Ya! All was not lost!

#1 2015-11-12 17:52:59

[SOLVED] Why the display manager kicks off first?

#2 2015-11-12 18:07:00

Re: [SOLVED] Why the display manager kicks off first?

#3 2015-11-12 20:30:09

Re: [SOLVED] Why the display manager kicks off first?

#4 2015-11-12 20:41:02

Re: [SOLVED] Why the display manager kicks off first?

#5 2015-11-12 21:01:18

Re: [SOLVED] Why the display manager kicks off first?

#6 2015-11-13 03:11:18

Re: [SOLVED] Why the display manager kicks off first?

#7 2015-11-13 06:57:16

Re: [SOLVED] Why the display manager kicks off first?

#8 2015-11-13 10:41:45

Re: [SOLVED] Why the display manager kicks off first?

#9 2015-11-13 14:07:13

Re: [SOLVED] Why the display manager kicks off first?

#10 2015-11-13 16:45:52

Re: [SOLVED] Why the display manager kicks off first?

#11 2015-11-13 17:12:10

Re: [SOLVED] Why the display manager kicks off first?

#12 2015-11-13 19:45:51

Re: [SOLVED] Why the display manager kicks off first?

#13 2015-11-13 19:55:19

Re: [SOLVED] Why the display manager kicks off first?

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