[Intel-gfx] [PATCH] drm/i915: Fallback to using unmappable memory for scanout

[shuang.he at intel.com]

Tested-By: PRC QA PRTS (Patch Regression Test System Contact: shuang.he at intel.com)
Task id: 6000
-------------------------------------Summary-------------------------------------
Platform          Delta          drm-intel-nightly          Series Applied
PNV                 -1              272/272              271/272
ILK                                  301/301              301/301
SNB                                  303/303              303/303
IVB                 -1              342/342              341/342
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_gem_userptr_blits_minor-sync-interruptible      PASS(2)      DMESG_WARN(1)PASS(1)
*IVB  igt_gem_storedw_batches_loop_secure-dispatch      PASS(2)      DMESG_WARN(1)PASS(1)
Note: You need to pay more attention to line start with '*'