It happened again, attaching Xorg.0.log now. Was able to move my mouse during the incident.
On 05/14/2014 10:55 PM, bugzilla-daemon@freedesktop.org wrote:

> Chris Wilson changed bug 78710

> What | Removed | Added
> --- | --- | ---
> Status | NEW | NEEDINFO
> Assignee | xorg-team@lists.x.org | chris@chris-wilson.co.uk
> QA Contact | xorg-team@lists.x.org | intel-gfx-bugs@lists.freedesktop.org
> Component | Lib/Xfont | Driver/intel

> Comment # 1 on bug 78710 from Chris Wilson

>     Sounds more likely to be a GPU issue. Please attach Xorg.0.log and
>     /sys/class/card0/error after one of these events.

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