A good reference for GDM3 config?

[graemev2]

Having got buster running on a "desktop" machine. 1st step was run Synaptic to install all the good stuff. Does not work, luckily I installed a large choice of GUIs , so log out, choose cinnamon, all is well. Next time I login defaults back to gnome+Wayland, so nothing works again. I search around and find and implement all the following to get it to default to cinnamon but no joy:

https://superuser.com/questions/685970/ ... stem-start

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$ cat ~/.dmrc 
[Desktop]
Language=en_GB.utf8
Session=cinnamon

https://superuser.com/questions/685970/ ... stem-start

Looks like this file is getting rewritten:

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$ ls -l /var/lib/AccountsService/users/graeme 
-rw-r--r-- 1 root root 179 May 24 12:19 /var/lib/AccountsService/users/graeme
$ date
Sun 24 May 13:12:55 BST 2020
$ cat /var/lib/AccountsService/users/graeme 
[org.freedesktop.DisplayManager.AccountsService]
BackgroundFile='/usr/share/images/desktop-base/desktop-background'

[User]
Language=
XSession=lightdm-xsession
SystemAccount=true

There seems to be no man page for /etc/gdm3/daemon.conf and gdm3(8) is pretty light on details.

So I end up on https://help.gnome.org/admin/gdm/3.26/c ... on.html.en

Lots of info, but either it's not complete, or there are options missing:

So my UID=501 and I want my default GUI to be cinnamon :

[greeter]
IncludeAll=true

Says

Any users with a user id less than 500 (or 100 if running on Oracle Solaris) are filtered out.

Well my 501 is being filtered out, so I'd like to change that to say 100 , can't see how

Can't see a way to make cinnamon the default?

Now I guess I could just delete all the other choices from /usr/share/xsessions, but that feels like the school of hit it 'till it works.

So I simply want:

1: My userid to appear as a choice on the XDM
2: My chosen GUI default to be remembered

Seems a pretty simple requirement , I've tried to RTFM for various "flavours" of FM but no joy. is there a good "HOWTO" somewhere? ( a full syntax description for /etc/gdm3/daemon.conf seems like what I need, but I'm prepared to disabused of that notion)

[Head_on_a_Stick]

log out, choose cinnamon, all is well. Next time I login defaults back to gnome+Wayland

I cannot reproduce your problem, if I select an alternative session in GDM (by clicking on the cog-wheel icon underneath the username login box) then that choice remains selected until I change it again. This is the default behaviour and no custom configuration is required.

Dirty hack to get synaptic working under Wayland:

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mkdir ~/bin
tee ~/bin/synaptic-pkexec <<END
#!/bin/sh
xhost +local:
x-terminal-emulator -e sudo synaptic
xhost -local:
END
chmod +x ~/bin/synaptic-pkexec

But don't tell anybody I told you how to do that...

[graemev2]

But don't tell anybody I told you how to do that...

... did you hear that? no, me neither?

To add a little to the saga (I'd assumed prior to your post, this was intended new behaviour) . If

1: Logon via gdm3 , use the little cog to select "cinnamon" (get cinnamon)
2: Log-out, login again via gdm3 , the little cog has cinnamon already ticked, get cinnamon
3: reboot (clean shutdown) login via gdm3, little cog has gnome ticked (Wayland flavour) selected , get gnome3

So my default is getting reset at a reboot, not a logoff&on

(still no takers of documentation for the config ?)

[kedaha]

1st step was run Synaptic to install all the good stuff. Does not work, luckily I installed a large choice of GUIs ...

Doesn't that result in crowded desktop environments? It seems to me things might get a bit bloated with all the icons, drop-down menus, launchers and other cruft. I wonder how that might be avoided since one computer could be used by several users who might prefer different desktop environments.

[graemev2]

Doesn't that result in crowded desktop environments

I'm guessing you've not done this (sorry if you have , but other readers may not) so if you
install say "cinnamon", "xfce" (probably kde , not tried) gnome3 etc ..then what SHOULD happen.

Each user who directly [ eg on a PC using the built-in graphics card with say a USB keyboard and mouse] uses that desktop (gdm3 in this case) gets to choose which GUI they see. They can swap from one login session to another , but unless they do they each gets the "same one they used last time" (from head on sticks explanation ...also historical behaviour) If users access this computer using a different Xterminal it gets a little more complicated.

So TOM might always see xfce
RICHARD might see cinnamon
HARRY might see gnome3

[graemev2]

[
if I select an alternative session in GDM (by clicking on the cog-wheel icon underneath the username login box) then that choice remains selected until I change it again. This is the default behaviour and no custom configuration is required.

I tried to create a new user "guest", he behaves as one expects (session type is remembered between logon & indeed reboot)

If I read more of the docs:
https://help.gnome.org/admin/gdm/3.26/c ... sionconfig

I see it explicitly states:

The user's default session and language choices are stored in the ~/.dmrc file. When a user logs in for the first time, this file is created with the user's initial choices. ...

If I look:

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root@real:/home/graeme# ls /home/*/.dmrc 
/home/graeme/.dmrc

Only I (the broken account) have a .dmrc file ....The other users (e.g. guest) don't have one but DO remember their previous session type
So I removed it (it dates from 2015)

No change in behaviour AND it did not get recreated (as per docs) when I logged on.

My best guess is there is some artefact in my account only , left from a previous install. However the discrepancies in the documentation make it hard to untangle.

ABTW. I created a uid=601 , he also does not appear in GDM3 choices (I'm betting on 1000 being the magic number ...whos config I can't find documentation for)

[cuckooflew]

graemev2 » I'm guessing you've not done this (sorry if you have , but other readers may not) so if you
install say "cinnamon", "xfce" (probably kde , not tried) gnome3 etc ..then what SHOULD happen.

No, of course not, Why on earth would anyone want to install all of that bloat ?

1st step was run Synaptic to install all the good stuff. Does not work, luckily I installed a large choice of GUIs ...

Doesn't that result in crowded desktop environments? It seems to me things might get a bit bloated with all the icons, drop-down menus, launchers and other cruft. I wonder how that might be avoided since one computer could be used by several users who might prefer different desktop environments.

Yes it does, and as we can see , it get's more and more complicated , problematic, etc. (below)

graemev2 >Does not work, luckily I installed a large choice of GUIs , so log out, choose cinnamon, all is well. Next time I login defaults back to gnome+Wayland, so nothing works again

Install 1 good simple Window Manager, and if every Tom,**** and Harry don't like it , they can get their own computers and install what ever bloat they want.
So any way, back to the topic, based on the title:
A good reference for GDM3 config?
One of many hits, and a good referance:
https://debian-handbook.info/browse/sta ... rface.html

BACK TO BASICS Window manager
True to the Unix tradition of doing one thing only but doing it well, the window manager displays the “decorations” around the windows belonging to the currently running applications, which includes frames and the title bar. It also allows reducing, restoring, maximizing, and hiding windows. Most window managers also provide a menu that pops up when the desktop is clicked in a specific way. This menu provides the means to close the window manager session, starting new applications, and in some cases, change to another window manager (if installed).

[graemev2]

Cracked it!

It's the UID (again!) :

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$ sudo useradd -c "uid is 666" -m -u 666 user666

$ sudo passwd user666
New password: 
Retype new password: 
passwd: password updated successfully

Now the user user666. If you goto the GDM3 screen.

1: Its not listed (it should be as it's over 500)
2: Type the username , then enter/next , choose the cog ..it's gnome3(wayland) change it to xfce
3: find yourself in a normal xfce session ....logout
4: goto gdm3, type user666, got to cog, it says "xfce"
5: reboot the system
6: goto the gdm3, type user666, got the cog ...it says ..."gnome3"

Looks like low userids are NOT listed and also do not store their settings persistently

I also switched to lightdm :

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sudo dpkg-reconfigure gdm3

This managed to save the defaults for all users (so guess what I'm doing?)

[graemev2]

Install 1 good simple Window Manager, and if every Tom,**** and Harry don't like it , they can get their own computers and install what ever bloat they want.

Not entirely sure what you're trying to get at here.

1: I wasn't sure of user kedaha I wondered if they thought you might end up with 3 or 4 desktop GUIs at the same time. Just trying to reassure him he could install *All* of them they try each in turn 'till he found one he liked

2: If your point was that by using synaptic to install software I'd get a cluttered desktop ...OK , but that's' how I like to use a desktop

3: If your point was that all these modern GUIs have become very self absorbed and fail to address the original goal, I'd hearty agree (but please have that conversation in a different thread, there is a bug to stamp on here) . Personal I'm happy to start X by typing "X" the using the right mouse button to get an xterm ..If I needed decoration I used Toms window manager (TWM) . I got annoyed when my Athena widgets based client stopped working when they imposed the xhost + style security ( it popped an image of a pub on everyone's x-terminal with a "fancy the pub checkbox" [like the MIT tea Lady client])

[Head_on_a_Stick]

I missed this:

So my UID=501

Why? The default first user ID should be 1000 (as per adduser.conf(5) & /etc/adduser.conf).

[graemev2]

Why? The default first user ID should be 1000 (as per adduser.conf(5) & /etc/adduser.conf).

I use NFSv3 and my NAS allocates userids in the range starting at 500

[Head_on_a_Stick]

my NAS allocates userids in the range starting at 500

That makes no sense at all, user IDs are allocated when the user is created

Please post the output of

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grep "$USER" /etc/passwd

[graemev2]

V.odd... I pretty sure I replied to this (so sorry if it duplicates)

On this debain box:

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$ grep $USER /etc/passwd
graeme:x:501:100:Graeme Vetterlein:/home/graeme:/bin/bash

On the NAS:

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grep graeme /etc/passwd
graeme:x:501:100:Linux User,graeme.qnap451plus@<elided>,,:/share/homes/graeme:/bin/sh

On another (squeeze) box

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$ grep $USER /etc/passwd
graeme:x:501:100:Graeme Vetterlein,,,:/home/graeme:/bin/bash

Obviously they all need to be the same for NFSv3 to work. The NAS imposes the number, it's not just a generic Linux box

When this is finally set up, I plane to move the passwd off to NIS (yellow pages) or, if I can figure it out LDAP (which the NAS has a preference for) So the pid here will only apply in non-networked modes.