[Intel-gfx] [PATCH v4] drm/i915: Optimistically spin for the request completion

[shuang.he at intel.com]

Tested-By: PRC QA PRTS (Patch Regression Test System Contact: shuang.he at intel.com)
Task id: 6019
-------------------------------------Summary-------------------------------------
Platform          Delta          drm-intel-nightly          Series Applied
PNV                 -1              274/274              273/274
ILK                                  303/303              303/303
SNB                                  303/303              303/303
IVB                                  342/342              342/342
BYT                                  287/287              287/287
HSW                                  362/362              362/362
BDW                                  308/308              308/308
-------------------------------------Detailed-------------------------------------
Platform  Test                                drm-intel-nightly          Series Applied
*PNV  igt_gen3_render_linear_blits      PASS(5)      CRASH(1)PASS(1)
Note: You need to pay more attention to line start with '*'