Ubuntu :: Bootup Error Messages "render Ring Head Not Reset To Zero Ctl 00000000 Head 02001000 Tail 00000000 Start 02001000"

So everytime I resume Ubuntu from hibernation, it remains black for a time then 2 messages on the screen appear for about 10 seconds before I can log-in:

Code: [ 0.556247] [drm:init_ring_common] *ERROR* render ring head not reset to zero ctl 00000000 head 02001000 tail 00000000 start 02001000 [ 0.556320] [drm:init_ring_common] *ERROR* render ring head forced to zero ctl 00000000 head 00000000 tail 00000000 start 02001000