Few tests : *ERROR* Overflow of CRC buffer, userspace reads too slow.

http://gfx-ci.igk.intel.com/cibuglog-ng/testresult/1453981778?query_key=e0839929b9e74e65a048f1147cc702152f561a32

<4> [910.299383] hardirqs last disabled at (2112920): [<ffffffff81c8782f>] sysvec_irq_work+0xf/0xd0
<0> [910.310033] kworker/-214 11..... 141128910us : intel_rps_mark_interactive: 0000:00:02.0 mark interactive: no
<4> [910.320605] softirqs last enabled at (2112870): [<ffffffff81c9af7d>] __do_softirq+0x2bd/0x3a9
<0> [910.331357] kms_flip-1191 2..... 141154239us : intel_rps_mark_interactive: 0000:00:02.0 mark interactive: yes
<4> [910.341401] softirqs last disabled at (2112861): [<ffffffff810d721e>] irq_exit_rcu+0xae/0xf0
<0> [910.352629] kworker/-214 11..... 141156689us : intel_rps_mark_interactive: 0000:00:02.0 mark interactive: no
<4> [910.362724] ---[ end trace 0000000000000000 ]---
<0> [910.363209] kms_flip-1191 2..... 141182016us : intel_rps_mark_interactive: 0000:00:02.0 mark interactive: yes
<3> [911.915589] [drm:drm_crtc_add_crc_entry] *ERROR* Overflow of CRC buffer, userspace reads too slow.
<0> [911.924883] kworker/-214 11..... 141184465us : intel_rps_mark_interactive: 0000:00:02.0 mark interactive: no
<0> [911.954833] kms_flip-1191 2..... 141209835us : intel_rps_mark_interactive: 0000:00:02.0 mark interactive: yes
<0> [911.965529] kworker/-214 11..... 141212242us : intel_rps_mark_interactive: 0000:00:02.0 mark interactive: no
<0> [911.976094] kms_flip-1191 2..... 141237608us : intel_rps_mark_interactive: 0000:00:02.0 mark interactive: yes
<0> [911.986791] kworker/-214 11..... 141240018us : intel_rps_mark_interactive: 0000:00:02.0 mark interactive: no
<0> [911.997388] kms_flip-1191 2..... 141265337us : intel_rps_mark_interactive: 0000:00:02.0 mark interactive: yes
<0> [912.008044] kworker/-188 2..... 141267857us : intel_rps_mark_interactive: 0000:00:02.0 mark interactive: no
<0> [912.018656] kms_flip-1191 4..... 141332057us : __gt_unpark: 0000:00:02.0
<0> [912.026131] kms_flip-1191 4..... 141333643us : __gt_park: 0000:00:02.0
<0> [912.033531] kms_flip-1191 4..... 141334300us : __gt_unpark: 0000:00:02.0
<0> [912.040987] kms_flip-1191 4..... 141335780us : __gt_park: 0000:00:02.0
<0> [912.048377] kms_flip-1191 4..... 141338555us : __gt_unpark: 0000:00:02.0
<0> [912.055952] kms_flip-1191 4..... 141339422us : __intel_context_do_pin_ww: 0000:00:02.0 bcs0: context:18 active
<0> [912.066751] kms_flip-1191 4..... 141339972us : intel_timeline_pin: 0000:00:02.0 timeline:18 using HWSP offset:fedd0000
<0> [912.078135] kms_flip-1191 4..... 141340444us : __engine_unpark: 0000:00:02.0 bcs0: