Issue with DRI after latest update

[xtremyst inxtremo]

I removed xorg.conf and /root/xorg.conf.new, replaced xf86-video-ati with
xf86-video-ati-ums, rebooted and tried to startx, I could see a cursor in
the middle of the screen and a white square on the top left corner for a
couple of seconds and then screen goes blank (sometimes turning off and
sometimes stays on but completely blank), so I had to reset every time
(alt+ctrl+del didn't work most of the times).

I also tried to use my old xorg.conf with Driver  "radeon-ums" (no screen
found), and with Driver "radeon" but got the same behavior.
I also tried with vesa but resolution was low and DRI seemed again disabled
(no xv).
Finally I tried to run Xorg -configure but i got "Configuration failed:
Number of created screens does not match number of devices detected".
however it created a xorg.conf.new file in /root with two DevicesSection
parts, one that stated Driver "radeon" and one with Driver "vesa", I used
this to startx and it used vesa with the results I mentioned earlier.

On Wed, Nov 5, 2014 at 1:20 PM, Jean-Sébastien Pédron <
jean-sebastien.pedron at dumbbell.fr> wrote:

> On 04.11.2014 19:00, xtremyst inxtremo wrote:
> > Don't know how i missed this, running dmesg | grep RADEON_IS gives me:
> > info: [drm] RADEON_IS_PCI
>
> Could you please try with xf86-video-ati-ums? You need to deinstall
> xf86-video-ati first.
>
> I know that the last time you tried it, X failed to start. I think it's
> because the KMS driver was already loaded and currently, it can't be
> unloaded when vt(4) is used. You need to reboot then start X.
>
> --
> Jean-Sébastien Pédron
>
>