After instalation amdgpu-pro the screan doesn't display and i can see only corsour. I found the solution here amdgpu-pro-install on Ubuntu GNOME 16.04 with R9 285 and RX 480 but after exute a command apt-get source cogl there is error:
WARNING: packeting "cogl" is managed in system of control version "Svn" at:
It's necessary to download 1652 kB sources archives.
WARNING: Some packiets could be not verificated
E: Some packiets could be not verificated
Sorry my English is not very well. Error code is translated by me.