ok, I've tried catalyst 9.1 for some weeks and I discovered that:

-If I use underscan or overscan mode in the tv settings, it is ok, I don't get any black screens/crashes

-If I change the screen dimension manually, I get the blackscreen everyeime I standby or reboot, or restart X.

So at the moment I'm using overscan with custom calibration in xbmc/mythtv