Created attachment 112115 [details]
dmesg output

==System Environment==
--------------------------
Regression: No. I didn't find good commit for this case.
platform: BSW

==kernel==
--------------------------
origin/drm-intel-nightly: 1113d085dfdba11c64772bfb4da26d1d3a163512(fails)
origin/drm-intel-next-queued: 985850bd145655d10dfcd5a03a3fc38540794ca7(fails)
origin/drm-intel-fixes: e3e6efcd638d3caa18d9e89f235c7d6fc32c1f0b(fails)

==Bug detailed description==
-----------------------------
running case igt/gem_fence_upload/thread-contention will fail:
 ./gem_fence_upload  --run-subtest thread-contention
IGT-Version: 1.8-g1244fc6 (x86_64) (Linux: 3.19.0-rc3_drm-intel-nightly_1113d0_20150111+ x86_64)
Contended upload rate for 1 linear threads:     1393.607MiB/s
Contended upload rate for 1 tiled threads:      1420.076MiB/s
Contended upload rate for 2 linear threads:     967.410MiB/s
Contended upload rate for 2 tiled threads:      970.138MiB/s
Contended upload rate for 4 linear threads:     675.704MiB/s
Contended upload rate for 4 tiled threads:      683.534MiB/s
Contended upload rate for 8 linear threads:     610.603MiB/s
Contended upload rate for 8 tiled threads:      616.030MiB/s
Contended upload rate for 16 linear threads:    599.609MiB/s
Contended upload rate for 16 tiled threads:     597.937MiB/s
Contended upload rate for 32 linear threads:    595.678MiB/s
Contended upload rate for 32 tiled threads:     592.604MiB/s
Contended upload rate for 64 linear threads:    581.516MiB/s
Contended upload rate for 64 tiled threads:      59.982MiB/s
Test assertion failure function thread_contention, file gem_fence_upload.c:321:
Failed assertion: linear[1] > 0.75 * linear[0]
Subtest thread-contention: FAIL (22.113s)

Abnormal output in dmesg(more detail info please refer to the attachment):

dmesg -r |grep drm|grep '<[1-4]>'
<4>[    1.482341] WARNING: CPU: 1 PID: 1138 at drivers/gpu/drm/i915/intel_display.c:11933 intel_disable_plane+0x33/0x7c [i915]()
<4>[    1.482344] Modules linked in: i915 button video drm_kms_helper drm cfbfillrect cfbimgblt cfbcopyarea
<4>[    1.482345] CPU: 1 PID: 1138 Comm: kworker/u16:6 Not tainted 3.19.0-rc3_drm-intel-nightly_1113d0_20150111+ #282
<4>[    1.482459]  [<ffffffffa001813e>] ? drm_mode_set_config_internal+0x4e/0xd2 [drm]
<4>[    1.482461]  [<ffffffffa0063d16>] ? restore_fbdev_mode+0xa8/0xc3 [drm_kms_helper]
<4>[    1.482462]  [<ffffffffa0064f90>] ? drm_fb_helper_restore_fbdev_mode_unlocked+0x1f/0x56 [drm_kms_helper]
<4>[    1.482464]  [<ffffffffa0064ff5>] ? drm_fb_helper_set_par+0x2e/0x33 [drm_kms_helper]
<4>[    1.482506]  [<ffffffffa006524c>] ? drm_fb_helper_initial_config+0x252/0x2ef [drm_kms_helper]
<4>[    1.482541] WARNING: CPU: 1 PID: 1138 at drivers/gpu/drm/i915/i915_gem.c:4530 i915_gem_free_object+0x131/0x26b [i915]()
<4>[    1.482543] Modules linked in: i915 button video drm_kms_helper drm cfbfillrect cfbimgblt cfbcopyarea
<4>[    1.482544] CPU: 1 PID: 1138 Comm: kworker/u16:6 Tainted: G        W      3.19.0-rc3_drm-intel-nightly_1113d0_20150111+ #282
<4>[    1.482611]  [<ffffffffa0018191>] ? drm_mode_set_config_internal+0xa1/0xd2 [drm]
<4>[    1.482612]  [<ffffffffa0063d16>] ? restore_fbdev_mode+0xa8/0xc3 [drm_kms_helper]
<4>[    1.482614]  [<ffffffffa0064f90>] ? drm_fb_helper_restore_fbdev_mode_unlocked+0x1f/0x56 [drm_kms_helper]
<4>[    1.482615]  [<ffffffffa0064ff5>] ? drm_fb_helper_set_par+0x2e/0x33 [drm_kms_helper]
<4>[    1.482654]  [<ffffffffa006524c>] ? drm_fb_helper_initial_config+0x252/0x2ef [drm_kms_helper]


==Reproduce steps==
---------------------------- 
./gem_fence_upload  --run-subtest thread-contention