[  683.004539] WARNING: CPU: 6 PID: 1126 at /build/linux-lts-vivid-LIqOuh/linux-lts-vivid-3.19.0/ubuntu/i915/intel_pm.c:3406 skl_update_other_pipe_wm+0x210/0x220 [i915_bpo]()
[  683.004541] WARN_ON(!wm_changed)
[  683.004542] Modules linked in: btrfs xor raid6_pq ufs qnx4 hfsplus hfs minix ntfs msdos jfs xfs libcrc32c snd_hda_codec_hdmi snd_hda_codec_realtek snd_hda_codec_generic dell_wmi hid_generic sparse_keymap dell_laptop dcdbas snd_hda_intel x86_pkg_temp_thermal coretemp kvm_intel kvm snd_hda_controller crct10dif_pclmul crc32_pclmul snd_hda_codec snd_hwdep aesni_intel snd_pcm aes_x86_64 lrw gf128mul snd_seq_midi glue_helper ablk_helper snd_seq_midi_event cryptd btusb snd_rawmidi uvcvideo snd_seq snd_seq_device snd_timer joydev videobuf2_vmalloc nouveau videobuf2_memops serio_raw snd videobuf2_core i915_bpo v4l2_common videodev usbhid media brcmfmac hid brcmutil mxm_wmi soundcore cfg80211 ttm intel_ips drm_kms_helper drm i2c_algo_bit shpchp wmi int3403_thermal dell_smo8800 video rfcomm bnep bluetooth int3402_thermal int3400_thermal acpi_thermal_rel acpi_pad mac_hid binfmt_misc nls_iso8859_1 parport_pc ppdev lp parport psmouse ahci nvme libahci
[  683.004581] CPU: 6 PID: 1126 Comm: Xorg Tainted: G        W      3.19.0-49-generic #55~14.04.1-Ubuntu
[  683.004583] Hardware name: Dell Inc. XPS 15 9550/0N7TVV, BIOS 01.00.07 11/02/2015
[  683.004584]  ffffffffc0631268 ffff880496357598 ffffffff817b01b5 0000000000000000
[  683.004586]  ffff8804963575e8 ffff8804963575d8 ffffffff81074dea ffff880496357710
[  683.004588]  ffff8804a8a2e000 ffff880496357680 ffff880496357734 ffff8804a8a2a000
[  683.004590] Call Trace:
[  683.004596]  [<ffffffff817b01b5>] dump_stack+0x45/0x57
[  683.004599]  [<ffffffff81074dea>] warn_slowpath_common+0x8a/0xc0
[  683.004601]  [<ffffffff81074e66>] warn_slowpath_fmt+0x46/0x50
[  683.004612]  [<ffffffffc0570700>] skl_update_other_pipe_wm+0x210/0x220 [i915_bpo]
[  683.004622]  [<ffffffffc0570915>] skl_update_wm+0x205/0x850 [i915_bpo]
[  683.004638]  [<ffffffffc05bab0e>] ? gen9_read32+0x6e/0x2f0 [i915_bpo]
[  683.004649]  [<ffffffffc05719fe>] intel_update_watermarks+0x1e/0x30 [i915_bpo]
[  683.004666]  [<ffffffffc05d7ad0>] intel_finish_crtc_commit+0x190/0x1b0 [i915_bpo]
[  683.004674]  [<ffffffffc03246c9>] drm_atomic_helper_commit_planes_on_crtc+0x169/0x240 [drm_kms_helper]
[  683.004695]  [<ffffffffc05f1af8>] intel_atomic_commit+0x68/0x100 [i915_bpo]
[  683.004710]  [<ffffffffc036a1f7>] drm_atomic_commit+0x37/0x60 [drm]
[  683.004717]  [<ffffffffc0322e75>] drm_atomic_helper_disable_plane+0xf5/0x140 [drm_kms_helper]
[  683.004720]  [<ffffffff810bb7e9>] ? mutex_optimistic_spin+0x139/0x1f0
[  683.004722]  [<ffffffff81200a20>] ? poll_select_copy_remaining+0x130/0x130
[  683.004734]  [<ffffffffc0359cc0>] __setplane_internal+0x1d0/0x2c0 [drm]
[  683.004737]  [<ffffffff817b5636>] ? __ww_mutex_lock_slowpath+0x152/0x16c
[  683.004747]  [<ffffffffc0359ecc>] drm_mode_cursor_universal+0x11c/0x200 [drm]
[  683.004750]  [<ffffffff817b56af>] ? __ww_mutex_lock+0x5f/0x97
[  683.004759]  [<ffffffffc035a02c>] drm_mode_cursor_common+0x7c/0x1b0 [drm]
[  683.004762]  [<ffffffff81080757>] ? __sigqueue_free.part.12+0x37/0x40
[  683.004774]  [<ffffffffc035e301>] drm_mode_cursor_ioctl+0x41/0x50 [drm]
[  683.004782]  [<ffffffffc034eaac>] drm_ioctl+0x1ec/0x660 [drm]
[  683.004785]  [<ffffffff811ffda8>] do_vfs_ioctl+0x2f8/0x510
[  683.004787]  [<ffffffff810818f2>] ? __set_task_blocked+0x32/0x70
[  683.004790]  [<ffffffff811ecfd8>] ? __vfs_read+0x18/0x50
[  683.004806]  [<ffffffff81084356>] ? __set_current_blocked+0x36/0x90
[  683.004808]  [<ffffffff81200041>] SyS_ioctl+0x81/0xa0
[  683.004810]  [<ffffffff81084616>] ? SyS_rt_sigprocmask+0x86/0xb0
[  683.004813]  [<ffffffff817b7c0d>] system_call_fastpath+0x16/0x1b
[  683.004815] ---[ end trace 004e3ed937aefe93 ]---