10.3 system hangs when existing from X with radeon cards/driver

[Jin Guojun]

When using Radeon Video cards (X600/RV370, HD2400/RV610, HD4650/RV730) in FreeBSD 10.3, existing X causes system hanging.Event installed the xorg-7.7_2 with latest xf86-video-ati driver released on Feb 24, 2017, this problem still exists.
The xorg-7.7_2 in FreeBSD 11.0 and 12-Current do not have this problem.Has anyone seen this problem?And any suggestion on solving this problem on 10.3-R?
-Jin