gdm3 stalled

[Zener <zener78@xxxxxxxxx>]

After an upgrade several months ago, gdm3 get stalled at each boot and 
gnome can't run properly.

So, I've disabled gdm.service and gnome start properly without gdm.

All the upgrade system in these months have not been able to solve.

Could you help me to do an useful debug in order to solve?

Thanks.