I believe I am experiencing this issue also. Dell Optiplex 7040 with Intel I7-6700 (skylake) with integrated graphics (Intel HD 530) running Ubuntu 14.04.3 LTS.

Two monitors are connected via displayport cables. Issue also occurred when using displayport to DVI adapters.

The following is logged to /var/log/syslog every time I move the mouse cursor between screens. Occasionally when I move the mouse cursor to the other screen, the screen will blank and then a few seconds later come back on. Windows are not re-arranged (implying it is not the disappearance of a screen), and similar log entries are produced. No other rendering issues or graphics issues have been noted - Unity works fine. Running tuxracer does not cause any issues. 

If there is any additional information I can provide that would be helpful please let me know.

Feb  9 10:07:56 computer-name kernel: [595457.353689] ------------[ cut here ]------------
Feb  9 10:07:56 computer-name kernel: [595457.353710] WARNING: CPU: 4 PID: 1929 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]()
Feb  9 10:07:56 computer-name kernel: [595457.353711] WARN_ON(!wm_changed)
Feb  9 10:07:56 computer-name kernel: [595457.353712] Modules linked in: snd_seq_dummy cuse uas usb_storage vboxpci(OE) vboxnetadp(OE) vboxnetflt(OE) vboxdrv(OE) xt_conntrack ipt_MASQUERADE nf_nat_masquerade_ipv4 iptable_nat nf_conntrack_ipv4 nf_defrag_ipv4 nf_nat_ipv4 xt_addrtype iptable_filter ip_tables x_tables nf_nat nf_conntrack br_netfilter bridge stp llc aufs pci_stub rfcomm bnep bluetooth binfmt_misc twofish_generic twofish_avx_x86_64 twofish_x86_64_3way twofish_x86_64 twofish_common xts snd_hda_codec_hdmi snd_hda_codec_realtek snd_hda_codec_generic snd_hda_intel snd_hda_controller snd_hda_codec snd_hwdep snd_pcm snd_seq_midi snd_seq_midi_event snd_rawmidi joydev snd_seq snd_seq_device x86_pkg_temp_thermal coretemp snd_timer dell_wmi sparse_keymap kvm_intel dcdbas kvm snd serio_raw soundcore 8250_fintek i2c_hid mac_hid acpi_pad i915_bpo intel_ips drm_kms_helper drm i2c_algo_bit shpchp parport_pc ppdev lp parport nls_iso8859_1 dm_crypt hid_generic usbhid hid crct10dif_pclmul crc32_pclmul aesni_intel aes_x86_64 lrw gf128mul glue_helper ablk_helper cryptd e1000e psmouse ptp ahci pps_core nvme libahci wmi video [last unloaded: vboxdrv]
Feb  9 10:07:56 computer-name kernel: [595457.353749] CPU: 4 PID: 1929 Comm: Xorg Tainted: G        W  OE  3.19.0-49-generic #55~14.04.1-Ubuntu
Feb  9 10:07:56 computer-name kernel: [595457.353750] Hardware name: Dell Inc. OptiPlex 7040/0Y7WYT, BIOS 1.0.1 09/01/2015
Feb  9 10:07:56 computer-name kernel: [595457.353751]  ffffffffc05f4268 ffff88045cbb7598 ffffffff817b01b5 0000000000000000
Feb  9 10:07:56 computer-name kernel: [595457.353753]  ffff88045cbb75e8 ffff88045cbb75d8 ffffffff81074dea ffff88045cbb7710
Feb  9 10:07:56 computer-name kernel: [595457.353755]  ffff88045f18b000 ffff88045cbb7680 ffff88045cbb7734 ffff88045f18d000
Feb  9 10:07:56 computer-name kernel: [595457.353757] Call Trace:
Feb  9 10:07:56 computer-name kernel: [595457.353762]  [<ffffffff817b01b5>] dump_stack+0x45/0x57
Feb  9 10:07:56 computer-name kernel: [595457.353765]  [<ffffffff81074dea>] warn_slowpath_common+0x8a/0xc0
Feb  9 10:07:56 computer-name kernel: [595457.353767]  [<ffffffff81074e66>] warn_slowpath_fmt+0x46/0x50
Feb  9 10:07:56 computer-name kernel: [595457.353775]  [<ffffffffc0533700>] skl_update_other_pipe_wm+0x210/0x220 [i915_bpo]
Feb  9 10:07:56 computer-name kernel: [595457.353784]  [<ffffffffc0533915>] skl_update_wm+0x205/0x850 [i915_bpo]
Feb  9 10:07:56 computer-name kernel: [595457.353797]  [<ffffffffc057db0e>] ? gen9_read32+0x6e/0x2f0 [i915_bpo]
Feb  9 10:07:56 computer-name kernel: [595457.353806]  [<ffffffffc05349fe>] intel_update_watermarks+0x1e/0x30 [i915_bpo]
Feb  9 10:07:56 computer-name kernel: [595457.353820]  [<ffffffffc059aad0>] intel_finish_crtc_commit+0x190/0x1b0 [i915_bpo]
Feb  9 10:07:56 computer-name kernel: [595457.353827]  [<ffffffffc05076c9>] drm_atomic_helper_commit_planes_on_crtc+0x169/0x240 [drm_kms_helper]
Feb  9 10:07:56 computer-name kernel: [595457.353842]  [<ffffffffc05b4af8>] intel_atomic_commit+0x68/0x100 [i915_bpo]
Feb  9 10:07:56 computer-name kernel: [595457.353853]  [<ffffffffc04a81f7>] drm_atomic_commit+0x37/0x60 [drm]
Feb  9 10:07:56 computer-name kernel: [595457.353859]  [<ffffffffc0505e75>] drm_atomic_helper_disable_plane+0xf5/0x140 [drm_kms_helper]
Feb  9 10:07:56 computer-name kernel: [595457.353862]  [<ffffffff810bb7e9>] ? mutex_optimistic_spin+0x139/0x1f0
Feb  9 10:07:56 computer-name kernel: [595457.353870]  [<ffffffffc0497cc0>] __setplane_internal+0x1d0/0x2c0 [drm]
Feb  9 10:07:56 computer-name kernel: [595457.353873]  [<ffffffff817b5636>] ? __ww_mutex_lock_slowpath+0x152/0x16c
Feb  9 10:07:56 computer-name kernel: [595457.353880]  [<ffffffffc0497ecc>] drm_mode_cursor_universal+0x11c/0x200 [drm]
Feb  9 10:07:56 computer-name kernel: [595457.353882]  [<ffffffff817b56af>] ? __ww_mutex_lock+0x5f/0x97
Feb  9 10:07:56 computer-name kernel: [595457.353889]  [<ffffffffc049802c>] drm_mode_cursor_common+0x7c/0x1b0 [drm]
Feb  9 10:07:56 computer-name kernel: [595457.353892]  [<ffffffff81080757>] ? __sigqueue_free.part.12+0x37/0x40
Feb  9 10:07:56 computer-name kernel: [595457.353900]  [<ffffffffc049c301>] drm_mode_cursor_ioctl+0x41/0x50 [drm]
Feb  9 10:07:56 computer-name kernel: [595457.353906]  [<ffffffffc048caac>] drm_ioctl+0x1ec/0x660 [drm]
Feb  9 10:07:56 computer-name kernel: [595457.353910]  [<ffffffff811ffda8>] do_vfs_ioctl+0x2f8/0x510
Feb  9 10:07:56 computer-name kernel: [595457.353912]  [<ffffffff810818f2>] ? __set_task_blocked+0x32/0x70
Feb  9 10:07:56 computer-name kernel: [595457.353914]  [<ffffffff811ecfd8>] ? __vfs_read+0x18/0x50
Feb  9 10:07:56 computer-name kernel: [595457.353917]  [<ffffffff81084356>] ? __set_current_blocked+0x36/0x90
Feb  9 10:07:56 computer-name kernel: [595457.353918]  [<ffffffff81200041>] SyS_ioctl+0x81/0xa0
Feb  9 10:07:56 computer-name kernel: [595457.353921]  [<ffffffff817b7c0d>] system_call_fastpath+0x16/0x1b
Feb  9 10:07:56 computer-name kernel: [595457.353922] ---[ end trace ca051f728083824b ]---