X broken as drmSetMaster failed

That was a bad evening, I upgraded my debian box and X failed to start throwing below errors.

6017.269] (EE) modeset(0): drmSetMaster failed: Permission denied
[ 6017.269] (EE)
Fatal server error:
[ 6017.269] (EE) AddScreen/ScreenInit failed for driver 0

After spending hours I came to know latest X can’t run without root privilege now. We need to have legacy package of xserver to run X as non root user

sudo apt-get install xserver-xorg-legacy

then the wrapper config, so edit/create  /etc/X11/Xwrapper.config  to have the below two lines only.

allowed_users=console
needs_root_rights=yes

X is back, What a relief .