How to restore LightDM settings?

Question

I've been playing with some of the settings on simple LightDM manager, and I'm not really sure I like what I've done. I've uninstalled LightDM manager but settings remains.

How can I restore LightDM settings to their defaults?

Answer 1

I've had a look at this issue and it looks like simple-lightdm-manager affects one file called unity-greeter.conf.

1. Lets start by opening up a terminal, start typing "terminal" in your unity dash to see the option or press ctrl+alt+t

2. Lets go to the correct directory:

   cd /etc/lightdm
   

3. Now lets make a backup of the file before we make any changes:

   sudo cp unity-greeter.conf unity-greeter.conf.bak 
   

4. Now we need to open up this file and see whats changed, type/copy this:

   sudo gedit /etc/lightdm/unity-greeter.conf
   

   The file should look like below, but I'm guessing your background and logo lines will look different:

   #
   # background = Background file to use, either an image path or a color (e.g. #772953)
   # logo = Logo file to use
   # theme-name = GTK+ theme to use
   # font-name = Font to use
   # xft-antialias = Whether to antialias Xft fonts (true or false)
   # xft-dpi = Resolution for Xft in dots per inch (e.g. 96)
   # xft-hintstyle = What degree of hinting to use (hintnone, hintslight, hintmedium, or hintfull)
   # xft-rgba = Type of subpixel antialiasing (none, rgb, bgr, vrgb or vbgr)
   #
   [greeter]
   background=/usr/share/backgrounds/warty-final-ubuntu.png
   logo=/usr/share/unity-greeter/logo.png
   theme-name=Ambiance
   icon-theme-name=ubuntu-mono-dark
   font-name=Ubuntu 11
   xft-antialias=true
   xft-dpi=96
   xft-hintstyle=hintslight
   xft-rgba=rgb
   

5. Now either replace everything in your file with the code above, or replace the background and logo lines with the ones above. Then save and log out.

Be careful not to add anything else to this file it could cause adverse effects to your log in screen or even prevent you from logging in

The code above is the default file that loads with a fresh install of Ubuntu 11.10.

Answer 2

I had a problem with my box getting stuck at the Ubuntu logo. Hitting Alt+F1 took me to a prompt where I ran sudo apt-get --purge remove lightdm gdm -- I'm using gnome, not Unity. Be careful with this -- watch what else Ubuntu wants to remove.

In my case, Ubuntu removed gnome-core.

After it was done, I ran sudo apt-get install gnome which brought back gdm, gnome-core, etc with default configs. A reboot gave me back gdm and no longer was I stuck at the Ubuntu logo on boot.

Be careful with apt-get --purge remove!

Answer 3

sudo apt-get -o Dpkg::Options::="--force-confnew" install --reinstall lightdm will do it for you.

Answer 4

I found out that it's because during my installation of Ubuntu 11.10, I checked the, "Encrypted Home Folder," option. In doing a search about Simple LightDM Manager, I found out that if your Home Folder is encrypted, the app doesn't have privilages to the files that it needs to change your LightDM settings. I've changed the permissions of the files to hopefully allow Simple LighDM Manager to access them, but all I get is a black screen with the login prompts to the left. I can change the color, but cannot add an image of any type to the login screen. I tried removing Simple LightDM Manager and reinstalling the regular lightdm as described in the above answer, but to no avail. I am somewhat new to Ubuntu, so, I suppose I'm stuck with it, as there doesn't seem to be a way other than reinstalling the OS all over again, and NOT checking the encryption option whilst installing.

Answer 5

LightDM loads settings from multiple places. This list from the Ubuntu documentation page shows the load order, with later ones in this list overriding earlier locations.

LightDM configuration is provided by the following files:

/usr/share/lightdm/lightdm.conf.d/*.conf # System/package configs
/etc/lightdm/lightdm.conf.d/*.conf       # Package/system administrator configs
/etc/lightdm/lightdm.conf                # Generated by installer once, overrides others

System provided configuration is stored in /usr/share/lightdm/lightdm.conf.d/*.conf and is not normally user editable. System administrators (with sudo) can override this configuration in /etc/lightdm/lightdm.conf.d/*.conf and /etc/lightdm/lightdm.conf. Files are read in the above order and combined together to make the LightDM configuration.

For example, if you want to override the system configured default session (provided in /usr/share/lightdm/lightdm.conf.d/50-ubuntu.conf) you should make a file /etc/lightdm/lightdm.conf.d/50-myconfig.conf with the following:

[SeatDefaults]
user-session=mysession

An example file showing all the possible configuration is provided in /usr/share/doc/lightdm/lightdm.conf.gz.

If you went through the installer and filled out auto-login/etc then it was probably written to either /etc/lightdm/lightdm.conf or /etc/lightdm/lightdm.conf.d/*.conf. You can safely remove the /etc/lightdm/lightdm.conf to revert to system settings, and if you haven't made any changes to stuff in the /etc/lightdm/lightdm.conf.d/ directory then only the 50-ubuntu.conf and some other package configs should be in there.