Desktop Environment on ArchARM with RPi3

[obi8]

Hello guys,

i have a problem with my Desktop Environment. I install xorg, xorg driver for rpi, lightdm, lightdm-gtk-greeter,
mate and mate-extra.

The display manager start and i can login but if i do that, then i only see a black screen.
In the display manager i selected mate as a de.

What i must do to start mate(DE) correctly?