https://bugs.freedesktop.org/show_bug.cgi?id=100395
--- Comment #3 from Andy Furniss adf.lists@gmail.com --- Created attachment 130499 --> https://bugs.freedesktop.org/attachment.cgi?id=130499&action=edit dmesg
dmesg attached, plus a link to an external video of what it looks like.
As seen it's also visible when playing a vid, mpv is using opengl for output.
https://drive.google.com/file/d/0BxP5-S1t9VEEak90Tk9wM2dUVlU/view?usp=sharin...