Environment:
-------------------
Kernel: (drm-intel-next-queued)b7c0d9df97c10ec5693a838df2fd53058f8e9e96
Some additional commit info:
Author:     Daniel Vetter <daniel.vetter@ffwll.ch>
AuthorDate: Fri Apr 25 16:59:00 2014 +0200
Commit:     Daniel Vetter <daniel.vetter@ffwll.ch>
CommitDate: Fri Apr 25 16:59:00 2014 +0200

    drm/i915: Integrate cmd parser kerneldoc

    Ville noticed that we have this nice kerneldoc but it's not integrated
    anywhere. Fix this asap!

    Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
    Cc: Brad Volkin <bradley.d.volkin@intel.com>
    Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>


Description:
--------------------
run S4 test in a loop. system resume with hang. This issue is probabilistic, perhaps it will come up to your eyes for just a while S4 test or more. I remove i915 module,then I run 20 times. It works well.

Reproduce step:
----------------------
1.boot up machine with command "reboot"(warm boot)
2.echo 0 > /sys/class/rtc/rtc0/wakealarm ; 
  echo +10 > /sys/class/rtc/rtc0/wakealarm; 
3.echo disk > /sys/power/state
4.loop running step 2 and 3