User's Guide for LightDM?

[F M Waterman]

Greetings,

My systems are all running Linux Mint 18.2 with Cinnamon desktop. If my understanding is correct, the default display manager is LightDM.

I am interested in changing up the appearance of the login windows of two of my computers. I have found where the settings may be changed, however I do not understand all of the descriptions for the various fields, nor what they control exactly. I am wondering if anyone has written a user's guide for the LightDM display manager that is updated to this particular iteration? Searching for such a document has proven to be fruitless, so I thought I would ask among the knowledgeable people here,

Thank you.

[kc1di]

The best treatment of lightdm I've found is on the ArchWiki.
here:
https://wiki.archlinux.org/index.php/LightDM

It pretty much covers it all.

[F M Waterman]

Thank you VERY much!

I've only had a look at the outline for the wiki entry, but it looks to be quite thorough and it shouldn't be particularly difficult to 'transcode' the information for Mint/Ubuntu!

[F M Waterman]

You know, as I began to dig into the ArchWiki entry for the LightDM display manager, I began to wonder what sorts of goodies our repositories hold for Mint and Ubuntu users to use with LightDM. An update of the packages available from the repositories and a search of the parameter 'lightdm' provided me with a substantial list of available packages.

As I perused the list, many of the packages could readily be identified. The libraries, for example, or the package for LightDM itself and its configuration tool, but then there are other packages whose exact relationship to LightDM is not as clear to me as I would like it to be. I am hopeful that I might ask you to explain how these packages relate to LightDM so that, hopefully, I will become as knowledgeable as many of you are! (Yes! That IS a blatant schmooze, but sincerely meant!) . And on the chance that someone might be asking 'why don't you just Google the answers for yourself?', my response is 1) I DO NOT LIKE and DO NOT TRUST Google and 2) I DID perform several searches to try and find the answers on my own, but was unable to. Now, with the introductory 'pleasantries' dealt with, let's get down to the 'rat killin'"!

Of the packages available, the one whose purpose and function I understand the least is the unity-system-compositor. Just what is it supposed to accomplish (without getting into opinions about the Unity shell, if possible!)?

The ubuntu-defaults-builder package sounds like it allows you to create your own theme or the like to use with LightDM. Is that right?

Next come 5 'session' packages, each for a specific variant of Ubuntu. Are these like themes that are specific to the variant they're named for? Does that mean the lxgames-default-session would be incompatible with Mint, say or straight up Ubuntu? And just what IS the lxgames variant? I have not heard of that before. Nevermind. THAT I probably CAN find on my own!

Then there are 3 'default settings' packages for Mythbuntu, Ubuntu Studio, and Xubuntu. Again: Are these like themes specific to these variants? Can they be used with other variants? In which ways are they different from 'session' packages?

If, by chance, you may be wondering just who to curse for my morbid sense of curiosity, you can blame my parents, of course, but the REAL credit must go to the good Jesuit fathers in charge of my education after high school. They took my runaway curiosity, forged it and honed it until it was razor sharp. The only thing they either did not or were not able to do was to provide it a social conscience. THAT was a rude learning experience!

Okie dokie. That's all for now. And once again, I do thank you for getting me started!

[Mick-Cork]

Just a quick note to say LightDM is not the default in 18.2, it remains as MDM unless you install it.

Extract from the LM Blog (http://blog.linuxmint.com/?p=3306)...

How to switch from MDM to LightDM

First, install LightDM by typing the following commands in a terminal:

Code: Select all

apt install slick-greeter lightdm lightdm-settings apparmor

When asked to select a default display manager, select LightDM.

Then, remove MDM and reboot by typing the following commands in a terminal:

Code: Select all

apt remove mdm
sudo reboot

[F M Waterman]

While it is not my wish to dispute what you have written, in my instance the facts speak for themselves.

I also want you to know that I have not done anything at all to modify the display manager that was installed by default by the distribution of Mint 18.2.

Code: Select all

~ $ apt-cache policy lightdm

lightdm:
  Installed: 1.18.3-0ubuntu1.1
  Candidate: 1.18.3-0ubuntu1.1
  Version table:
 *** 1.18.3-0ubuntu1.1 500
        500 http://mirror.team-cymru.org/ubuntu xenial-updates/main amd64 Packages
        500 http://security.ubuntu.com/ubuntu xenial-security/main amd64 Packages
        100 /var/lib/dpkg/status
     1.18.1-0ubuntu1 500
        500 http://mirror.team-cymru.org/ubuntu xenial/main amd64 Packages

~ $ apt-cache policy mdm

mdm:
  Installed: (none)
  Candidate: 2.0.18+sonya
  Version table:
     2.0.18+sonya 700
        700 http://mirror.team-cymru.org/mint-packages sonya/upstream amd64 Packages
     0.1.3-2.1build1 500
        500 http://mirror.team-cymru.org/ubuntu xenial/universe amd64 Packages

~ $ 

As you can see, the display manager that was installed by default, on both my my systems actually, was LightDM. Why this should be so in the face of the blog you reference, I cannot say, but there it is.

You know, your statement that LightDM is not the default display manager for Mint 18.2 bothered me. Not because I have to be right all the time. Hell, I'm lucky to be right ANY of the time, but something about your claim just didn't wash with the facts as I understood them.

However, when I read the blog entry you cited, "How to upgrade to Linux Mint 18.2", it became clear where you got your mistaken belief. Quoting from the article:

"Same goes for the choice of display manager or the software selection. Brasero won’t be removed and MDM won’t be switched for LightDM on your behalf. You can decide to make these changes, but you certainly don’t have to."

It is now easy to see where the confusion arose. Prior to 18.2 MDM was the default display manager, but with 18.2 the default display manager was changed to LightDM. The article you quoted was simply stating that as you already had MDM installed you had the option to switch over to LightDM, but that it was not required.

Alles klar, herr kommissar?

[Mick-Cork]

That's interesting F M. Maybe there's a difference between updating from a previous 18 release or installing from a fresh ISO? Maybe someone else can shed some light for us. As an aside, I did switch from MDM to LightDM post upgrade and it made a noticeable improvement on both boot up and shutdown times. Very happy with it.

Edit - just saw your follow up, I concur

[MtnDewManiac]

This stuff is over my head and, to be honest, above my interest level (other than that I'm happy with the Mint 17 login stuff - from the grub menu that I've added a nice scenary background picture to all the way to <DING>, your desktop has arrived - which I'll try to figure out how to keep/install when I fully switch to a newer version of the distro).

But other people undoubtedly WILL be very much interested in this thread. Why, then, is it hidden in the Cinnamon desktop sub-forum? Seems to me like it ought to be in one of the "applies to every desktop flavor of Mint's main edition" sections. Or am I misunderstanding, and LightDM is ONLY included with the Cinnamon flavors of Mint, and the MATE, Xfce, and KDE flavors get something else altogether?

Regards,
MDM

[kc1di]

I can confirm that lightdm is installed by default on all new clean installs. mdm is not. So with 18.2 if you install fresh from dvd/usb you'll get ligthdm.
This is at least true in the Mate DE. I'm not sure how long MDM is going to be supported after 18.2. I think it will eventually be dropped.

[Pjotr]

As kc1di says. A clean installation of 18.2 will always give you LightDM and not MDM. No matter what desktop edition. By default.

It's only when you upgrade from an older Mint version (18 or 18.1) to 18.2, that you keep the MDM you already had. Upgrades follow the Mint principle of being as little invasive as possible.....

[Hoser Rob]

... on the chance that someone might be asking 'why don't you just Google the answers for yourself?', my response is 1) I DO NOT LIKE and DO NOT TRUST Google and 2) I DID perform several searches to try and find the answers on my own, but was unable to. ...

I don't use Google Search either. I prefer Startpage HTTPS. But using the best search engine in the world won';t help if you don't know how to phrase the question.

[F M Waterman]

... on the chance that someone might be asking 'why don't you just Google the answers for yourself?', my response is 1) I DO NOT LIKE and DO NOT TRUST Google and 2) I DID perform several searches to try and find the answers on my own, but was unable to. ...

I don't use Google Search either. I prefer Startpage HTTPS. But using the best search engine in the world won';t help if you don't know how to phrase the question.

As true a statement as ever I heard! Personally, I'm smitten with duckduckgo, but everyone to their own tastes. If it works for YOU, then it's all good!

You know, a while back I began working up the start of an article on tips to get more out of any search engine. Although it's based on my experience first with Google and its predecessors and with Duckduckgo, I wonder if it would be worthwhile to pull it out of mothballs and share it here?

Anyone care to share their thoughts?

[F M Waterman]

This stuff is over my head and, to be honest, above my interest level (other than that I'm happy with the Mint 17 login stuff - from the grub menu that I've added a nice scenary background picture to all the way to <DING>, your desktop has arrived - which I'll try to figure out how to keep/install when I fully switch to a newer version of the distro).

But other people undoubtedly WILL be very much interested in this thread. Why, then, is it hidden in the Cinnamon desktop sub-forum? Seems to me like it ought to be in one of the "applies to every desktop flavor of Mint's main edition" sections. Or am I misunderstanding, and LightDM is ONLY included with the Cinnamon flavors of Mint, and the MATE, Xfce, and KDE flavors get something else altogether?

Regards,
MDM

Well, MDM I guess I didn't stop to consider the general appeal that this discussion might have. I think you made a fine point though and apologies for too much Geekspeak, but it's a hazard one faces in a forum such as this. That said, if you EVER have a question about something, especially something I write, PLEASE! FOR THE LOVE OF GOD! Ask! Say What did you mean? or something similar. I WILL to my damnedest to promote your understanding of a topic, 'cause as I see it, that's what it's all about.

[mr_raider]

I can confirm that lightdm is installed by default on all new clean installs. mdm is not. So with 18.2 if you install fresh from dvd/usb you'll get ligthdm.
This is at least true in the Mate DE. I'm not sure how long MDM is going to be supported after 18.2. I think it will eventually be dropped.

One major caveat: The KDE version always uses SDDM. The other three behave as you describe.

[revian]

Just a quick note to say LightDM is not the default in 18.2, it remains as MDM unless you install it.

Extract from the LM Blog (http://blog.linuxmint.com/?p=3306)...

How to switch from MDM to LightDM

First, install LightDM by typing the following commands in a terminal:

Code: Select all

apt install slick-greeter lightdm lightdm-settings apparmor

When asked to select a default display manager, select LightDM.

Then, remove MDM and reboot by typing the following commands in a terminal:

Code: Select all

apt remove mdm
sudo reboot

I installed Mint 18.2 Cinnamon from a USB key on a laptop and lightdm is indeed installed by default, with mdm not installed at all. Perhaps lightdm is the default on Cinnamon?

[MtnDewManiac]

Well, MDM I guess I didn't stop to consider the general appeal that this discussion might have. I think you made a fine point though and apologies for too much Geekspeak, but it's a hazard one faces in a forum such as this.

I wasn't griping at you. At least, that wasn't my intention. As for "geekspeak" (which brings up visions of shady early carnival exhibits, lol), as you mentioned, it is kind of a fact of life unless you want to use words such as "magic" or "it just does, that's how."

I just... The only reason I even became aware of your thread was that it appeared as the most recent post in the Cinnamon sub-forum, therefore I saw it when I passed through the "Desktops & Window Managers" section on my way to the Xfce sub-forum. Otherwise, I'd have missed it.

This leads me to assume that other people - and ones who might have more than a passing interest in the subject - may miss it as well. Specifically, those who do not use the Cinnamon desktop.

If the thread were to be moved into a more general section, maybe more people would see it. Or maybe not, I don't know.

Aside from that, thanks for your participation in the forum, and for posting a topic that people ARE interested in!

Regards,
MDM