replacing slim by lxdm as login manager

This is copied from a post by shin
It is a complicated method and only use it if the following doesn't work for you:
#pacman -S lxdm
then

sudo systemctl disable slim.service,

then

sudo systemctl enable lxdm.service,

and reboot.

Complicated approach

What I did to replace slim with lxdm:
pacman -S lxdm

replaced the /etc/inittab line for slim with lxdm
x:5:respawn:/usr/sbin/lxdm >/dev/null 2>&1

apparently lxdm doesn't invoke ~/.xinitrc, I guess xdm,gdm and kdm do, as stated in ~/.xsession

so added this line to /etc/lxdm/Xsession:
[ -f ~/.xinitrc ] && . ~/.xinitrc

in /usr/share/xsessions/openbox.desktop replaced the Exec line with:
Exec="ck-launch-session dbus-launch /usr/bin/openbox-session"

commented out the exec line in ~/.xinitrc
#exec ck-launch-session dbus-launch /usr/bin/openbox-session

on first login with lxdm select the openbox session from the drop down menu,
to make openbox default in lxdm change default session in /etc/lxdm/lxdm.conf
session="ck-launch-session dbus-launch /usr/bin/openbox-session" (this works but I'm not sure if its better to launch openbox like that or by selecting openbox in lxdm drop down menu that actually invokes /usr/share/xsessions/openbox.desktop)

With this setup everything works for me, mounts and everything I added to ~/.xinitrc.

To switch between the two is a matter of replacing the /etc/inittab line and uncommenting the exec line in ~/.xinitrc.

To try it out:

sudo systemctl disable slim.service,

sudo systemctl enable lxdm.service,

and reboot.