Created attachment 633083 [details]
Output of journalctl -b | grep -i gdm

After Factory update to 20150430 display lower half blinks heavily
intermittently (2-5 seconds interval) when wayland is in use.

GDM uses wayland and blinks. If I start gnome-wayland blinking continues. If I
start normal gnome -session or Icewm -session blinking stops. If I boot with
previous kernel (3.19.4.-1) both gdm and gnome-wayland -session work as
expected.

journalctk -k -b -p err:

May 02 11:46:04 ti-5136.site kernel: cdc_ncm 1-1.2:1.6 enp0s26u1u2i6: kevent 12
may have been dropped
May 02 11:46:07 ti-5136.site kernel: [drm:ironlake_irq_handler [i915]] *ERROR*
CPU pipe A FIFO underrun
May 02 11:46:07 ti-5136.site kernel: [drm:intel_set_pch_fifo_underrun_reporting
[i915]] *ERROR* uncleared pch fifo underrun on pch transcoder A
May 02 11:46:07 ti-5136.site kernel: [drm:cpt_irq_handler [i915]] *ERROR* PCH
transcoder A FIFO underrun

journalctl -b | grep -i gdm -output is in the attachment

I'm happy to provide any additional information if requested.