[Intel-gfx] [PATCH 2/2] drm/i915: don't save/restore backlight hist

[shuang.he at intel.com]

Tested-By: PRC QA PRTS (Patch Regression Test System Contact: shuang.he at intel.com)
-------------------------------------Summary-------------------------------------
Platform: baseline_drm_intel_nightly_pass_rate->patch_applied_pass_rate
BYT: pass/total=291/291->291/291
PNV: pass/total=356/356->350/356
ILK: pass/total=372/372->364/372
IVB: pass/total=545/546->545/546
SNB: pass/total=380/380->379/380
HSW: pass/total=579/579->577/579
BDW: pass/total=434/435->434/435
-------------------------------------Detailed-------------------------------------
test_platform: test_suite, test_case, result_with_drm_intel_nightly(count, machine_id...)...->result_with_patch_applied(count, machine_id)...
PNV: Intel_gpu_tools, igt_gen3_mixed_blits, CRASH(1, M23)NRUN(2, M23)PASS(1, M25) -> CRASH(4, M23)
PNV: Intel_gpu_tools, igt_gen3_render_linear_blits, CRASH(3, M23)PASS(1, M25) -> CRASH(4, M23)
PNV: Intel_gpu_tools, igt_gen3_render_mixed_blits, CRASH(2, M23)NRUN(1, M23)PASS(1, M25) -> CRASH(3, M23)NRUN(1, M23)
PNV: Intel_gpu_tools, igt_gen3_render_tiledx_blits, CRASH(1, M23)NRUN(2, M23)PASS(1, M25) -> CRASH(3, M23)NRUN(1, M23)
PNV: Intel_gpu_tools, igt_gen3_render_tiledy_blits, CRASH(2, M23)NRUN(1, M23)PASS(1, M25) -> CRASH(3, M23)DMESG_WARN(1, M23)
PNV: Intel_gpu_tools, igt_kms_sysfs_edid_timing, FAIL(1, M23)PASS(3, M25M23) -> FAIL(1, M23)PASS(3, M23)
ILK: Intel_gpu_tools, igt_drv_suspend_fence-restore-untiled, PASS(4, M26) -> DMESG_WARN(1, M26)PASS(3, M26)
ILK: Intel_gpu_tools, igt_kms_flip_bcs-wf_vblank-vs-dpms, DMESG_WARN(2, M26)PASS(2, M26) -> DMESG_WARN(1, M26)PASS(3, M26)
ILK: Intel_gpu_tools, igt_kms_flip_bcs-wf_vblank-vs-dpms-interruptible, DMESG_WARN(3, M26)PASS(1, M26) -> DMESG_WARN(2, M26)PASS(2, M26)
ILK: Intel_gpu_tools, igt_kms_flip_flip-vs-wf_vblank-interruptible, DMESG_WARN(1, M26)PASS(3, M26) -> DMESG_WARN(1, M26)PASS(3, M26)
ILK: Intel_gpu_tools, igt_kms_flip_plain-flip, PASS(4, M26) -> DMESG_WARN(2, M26)PASS(2, M26)
ILK: Intel_gpu_tools, igt_kms_flip_vblank-vs-hang-interruptible, PASS(4, M26) -> DMESG_WARN(1, M26)PASS(3, M26)
ILK: Intel_gpu_tools, igt_kms_pipe_crc_basic_bad-nb-words-1, PASS(4, M26) -> DMESG_WARN(1, M26)PASS(3, M26)
ILK: Intel_gpu_tools, igt_kms_setmode_invalid-clone-single-crtc, FAIL(2, M26)DMESG_FAIL(1, M26)TIMEOUT(12, M37M6)PASS(1, M26) -> TIMEOUT(1, M26)PASS(3, M26)
IVB: Intel_gpu_tools, igt_gem_bad_reloc_negative-reloc, NSPT(4, M21M34)PASS(6, M34M21) -> NSPT(1, M34)PASS(3, M34)
IVB: Intel_gpu_tools, igt_kms_setmode_invalid-clone-single-crtc, TIMEOUT(9, M34M21)PASS(1, M21) -> TIMEOUT(1, M34)PASS(3, M34)
SNB: Intel_gpu_tools, igt_kms_setmode_invalid-clone-single-crtc, TIMEOUT(17, M35M22)PASS(1, M35) -> TIMEOUT(1, M35)PASS(3, M35)
HSW: Intel_gpu_tools, igt_kms_flip_blocking-absolute-wf_vblank, PASS(4, M39) -> DMESG_WARN(1, M39)PASS(3, M39)
HSW: Intel_gpu_tools, igt_kms_setmode_clone-single-crtc, PASS(4, M39) -> DMESG_WARN(1, M39)PASS(3, M39)
BDW: Intel_gpu_tools, igt_gem_reset_stats_ban-bsd, DMESG_WARN(1, M28)PASS(12, M42M30M28) -> PASS(4, M28)
BDW: Intel_gpu_tools, igt_kms_setmode_invalid-clone-single-crtc, TIMEOUT(10, M42M30M28)PASS(1, M28) -> TIMEOUT(1, M28)PASS(3, M28)