Created attachment 99943 [details]
dump from /sys/class/drm/card0/error

I got this in my dmesg today:

[Tue May 27 13:54:44 2014] [drm:ring_stuck] *ERROR* Kicking stuck wait on blitter ring
[Tue May 27 13:54:44 2014] [drm] GPU crash dump saved to /sys/class/drm/card0/error
[Tue May 27 13:54:44 2014] [drm] GPU hangs can indicate a bug anywhere in the entire gfx stack, including userspace.
[Tue May 27 13:54:44 2014] [drm] Please file a _new_ bug report on bugs.freedesktop.org against DRI -> DRM/Intel
[Tue May 27 13:54:44 2014] [drm] drm/i915 developers can then reassign to the right component if it's not a kernel issue.
[Tue May 27 13:54:44 2014] [drm] The gpu crash dump is required to analyze gpu hangs, so please always attach it.
[Tue May 27 14:00:39 2014] kvm: zapping shadow pages for mmio generation wraparound

So I attached the output from there to this bug report.

But my laptop seemed to still be working fine and the display seemed ok, though at some point later in time (not sure when) the laptops screen was black and but the back light was still off. Enabling and disabling the laptop screen in ubuntu (xrandr) display manager brought the display back - it was connected to an external monitor via the eDocks DVI port and that remained fine the whole time.

Note that this is after my LCD and cabling were replaced today for 2nd time due to the LCD turning itself off though pretty sure the hardware fault due to the lvds cable is now fixed.