[Intel-gfx] [PATCH v2 2/2] drm/i915/bxt: work around HW coherency issue for cached GEM mappings

[shuang.he at intel.com]

Tested-By: Intel Graphics QA PRTS (Patch Regression Test System Contact: shuang.he at intel.com)
Task id: 7201
-------------------------------------Summary-------------------------------------
Platform          Delta          drm-intel-nightly          Series Applied
ILK                 -1              302/302              301/302
SNB                                  315/315              315/315
IVB                                  336/336              336/336
BYT                                  283/283              283/283
HSW                                  378/378              378/378
-------------------------------------Detailed-------------------------------------
Platform  Test                                drm-intel-nightly          Series Applied
*ILK  igt at kms_flip@flip-vs-dpms-interruptible      PASS(1)      DMESG_WARN(1)
Note: You need to pay more attention to line start with '*'