Intermitent black screens (Unbuntu 14.04.5/AMD 5350)

Hello,

I just upgraded from Kodi 16 to Kodi 17.

As a result, I got intermitent black screens (blinking)

Ubuntu Server 14.04.5
AMD 5350
Sony KDL32ex500 (HDMI)

Kodi.log : http://pastebin.com/rrznivWS

Except the black screens, everything works (video playback, audio, remote..)

Thanks