(In reply to intermediadc@hotmail.com from comment #16) > why im sure it is an xorg issue or one of xorg component issue > (cafedead),because on Lubuntu 14.04.5 i had kernel 4.9 and no issue but xorg > was 1.6 X has nothing to do with the kernel ring tests. Those happen long before X gets involved. If the ring tests fail, all acceleration is disabled so you need to sort out the kernel issue before addressing X.