Created attachment 113297
dmesg

==System Environment==
--------------------------
Bios : V68
Regression: No. First test on this platform.
boot with DP or HDMI monitor
Non-working platforms: SKLY

==kernel==
--------------------------
-nightly: b4442ee4e150506cebeee72249efc566c5f14bbe (fails)
     drm-intel-nightly: 2015y-02m-06d-09h-25m-00s UTC integration manifest

==Bug detailed description==
-----------------------------
testdisplay -a cause Call Trace

Detail:
[ 1242.330637] ------------[ cut here ]------------
[ 1242.330681] WARNING: CPU: 0 PID: 1361 at drivers/gpu/drm/i915/intel_pm.c:3084 skl_update_other_pipe_wm+0xe3/0x156 [i915]()
[ 1242.330694] WARN_ON(!wm_changed)
[ 1242.330697] Modules linked in: dm_mod snd_hda_codec_hdmi ppdev snd_hda_codec_realtek snd_hda_codec_generic snd_hda_intel pcspkr snd_hda_controller snd_hda_codec snd_
hwdep i2c_i801 snd_pcm snd_timer snd soundcore wmi battery parport_pc parport ac acpi_cpufreq i915 button video drm_kms_helper drm cfbfillrect cfbimgblt cfbcopyarea
[ 1242.330728] CPU: 0 PID: 1361 Comm: kworker/0:2 Not tainted 3.19.0-rc7_drm-intel-nightly_b4442e_20150208+ #198
[ 1242.330732] Hardware name: Intel Corporation Skylake Client platform/Skylake Y LPDDR3 RVP3, BIOS SKLSE2R1.86C.B068.R00.1501090908 01/09/2015
[ 1242.330757] Workqueue: events i915_hotplug_work_func [i915]
[ 1242.330760]  0000000000000000 0000000000000009 ffffffff8179a69b ffff88009b95b808
[ 1242.330764]  ffffffff8103bdec ffff880143e7991c ffffffffa008d5f4 ffff88009bba1000
[ 1242.330768]  ffff880143e79918 ffff88009b95b8d0 ffff880148813800 ffff880143ed6000
[ 1242.330773] Call Trace:
[ 1242.330783]  [<ffffffff8179a69b>] ? dump_stack+0x40/0x50
[ 1242.330791]  [<ffffffff8103bdec>] ? warn_slowpath_common+0x98/0xb0
[ 1242.330806]  [<ffffffffa008d5f4>] ? skl_update_other_pipe_wm+0xe3/0x156 [i915]
[ 1242.330812]  [<ffffffff8103be9c>] ? warn_slowpath_fmt+0x45/0x4a
[ 1242.330828]  [<ffffffffa008d5f4>] ? skl_update_other_pipe_wm+0xe3/0x156 [i915]
[ 1242.330844]  [<ffffffffa008d7a6>] ? skl_update_wm+0x13f/0x5a8 [i915]
[ 1242.330851]  [<ffffffff81065284>] ? add_wait_queue+0x3c/0x3c
[ 1242.330877]  [<ffffffffa00db2c8>] ? haswell_crtc_enable+0x580/0x9b2 [i915]
[ 1242.330900]  [<ffffffffa00d9878>] ? __intel_set_mode+0x7e5/0x895 [i915]
[ 1242.330923]  [<ffffffffa00df2d3>] ? intel_crtc_set_config+0x7d0/0xbb9 [i915]
[ 1242.330936]  [<ffffffffa0024a11>] ? drm_atomic_state_clear+0xec/0x10d [drm]
[ 1242.330952]  [<ffffffffa001804a>] ? drm_mode_set_config_internal+0x4e/0xd2 [drm]
[ 1242.330960]  [<ffffffffa00652e2>] ? restore_fbdev_mode+0xa8/0xc3 [drm_kms_helper]
[ 1242.330968]  [<ffffffffa00665ff>] ? drm_fb_helper_restore_fbdev_mode_unlocked+0x1f/0x56 [drm_kms_helper]
[ 1242.330975]  [<ffffffffa0066664>] ? drm_fb_helper_set_par+0x2e/0x33 [drm_kms_helper]
[ 1242.330982]  [<ffffffffa00665da>] ? drm_fb_helper_hotplug_event+0xa2/0xa8 [drm_kms_helper]
[ 1242.330989]  [<ffffffff8104d128>] ? process_one_work+0x1ad/0x31a
[ 1242.330995]  [<ffffffff8104d4ef>] ? worker_thread+0x235/0x330
[ 1242.331001]  [<ffffffff8104d2ba>] ? process_scheduled_works+0x25/0x25
[ 1242.331006]  [<ffffffff81050dee>] ? kthread+0xc5/0xcd
[ 1242.331011]  [<ffffffff81050d29>] ? kthread_freezable_should_stop+0x40/0x40
[ 1242.331029]  [<ffffffff8179ffec>] ? ret_from_fork+0x7c/0xb0
[ 1242.331033]  [<ffffffff81050d29>] ? kthread_freezable_should_stop+0x40/0x40
[ 1242.331037] ---[ end trace b15a6acb1a667d5d ]---
[ 1242.331071] [drm:skl_wm_flush_pipe] flush pipe A (pass 1)


==Reproduce steps==
---------------------------- 
1. boot with DP or HDMI monitor
2. ./testdisplay -a
3. check dmesg