using lightdm to replace gdm in fedora
I’ve been tracking F17 bug 816764 which I wrote about earlier; the latest comments suggested using LightDM to replace GDM on the system – hey why not, I’m using XFCE so don’t really need GDM – let’s give it a whirl. Turns out I like it!
Assuming you’re on XFCE (if you’re using GNOME/KDE your mileage will vary here) it’s very simple and easy to get working; LightDM is broken into two parts, the core code and the sub-packages for the “greeter”. Right now in F17 there are two greeters – gtk and kde.
yum install lightdm-gtk
In the most simple case, to get it working you simply need to add one variable to /etc/sysconfig/desktop:
All set! Do a quick reboot (I did just to ensure that GDM went away completely) and you have the new environment. Basically the /etc/X11/prefdm script sees that DISPLAYMANAGER and execs it. LightDM itself – by default from the RPM – then looks at /usr/share/xgreeters/lightdm-greeter.desktop which is a symlink to /etc/alternatives/lightdm-greeter which is then a symlink back to /usr/share/xgreeters/lightdm-gtk-greeter.desktop. This means if you want to have multiple greeter modules installed (gtk and kde, e.g.) then using the alternatives subsystem can flip them around easily.
Back on track, there are two main configs (and a few others but I didn’t need to mess with them) – /etc/lightdm/lightdm.conf (main config) and /etc/lightdm/lightdm-gtk-greeter.conf for the GTK greeter. I did not have to touch anything in the main config, but I did set up my GTK greeter like so by editing the /etc/lightdm/lightdm-gtk-greeter.conf file:
[greeter] background=#152233 show-language-selector=false theme-name=Adwaita font-name=Luxi Sans 12 xft-antialias=true xft-hintstyle=hintnone xft-rgba=rgb
These settings match my actual desktop (on this laptop/LED screen font-hinting looks horrible) so my LightDM greeter looks just light my login which is really cool, as well as not burning time on a PNG/JPG background I just have a basic color of dark blue. With GDM I was using a PNG file of the exact same color.
NOTE: while poking around lightdm I found a very tiny bug in the upstart config file; if you’re actually using upstart (probably 0.01% are) then see this bug I just submitted. I never even realized upstart was available in F17. :)