Ubuntu - в black screen after GRUB меню since upgrading from 14.04

When my update failed going from 14.04 to 15.10, I tried formatting and doing в fresh install of 15.10

That didn't work (гll explain now) so I tried Ubuntu-MATE 15.04 fresh install, лягание I thought if гm gonna resintall linux, might aswell try в different desktop, and maybe an older версия will work. Anyway what's been happening is that when I choose ubuntu from GRUB меню, most of the украл I just get в black screen with не backlight, but sometimes it boots. (And when I have the black screen I хан change the volume on the keyboard and hear в sound. Strange isn't it?)

When I boot in recovery mode I found an ошибка message that I think I managed to ответь тебе with

dmesg | egrep "drm|radeon"

Here is the output:

[   12.519822] [drm] Initialized drm 1.1.0 20060810
[   12.980446] [drm] VGACON disable radeon kernel modesetting.
[   12.980478] [drm:radeon_init [radeon]] *ERROR* No UMS support in radeon module!
[   13.007473] [drm] VGACON disable radeon kernel modesetting.
[   13.007502] [drm:radeon_init [radeon]] *ERROR* No UMS support in radeon module!

I have не разрабатывает what this means.

P.S, I Already tried removing the proprietary драйверы, and installing the open source radeon драйверы, and reinstalling the desktop and changing from lightdm to gdm невступил в брак it was lightdm not working.