I am not sure whether this is a real problem. However, every time I move my cursor from one screen to the other on a dual monitor system (i.e., laptop + external monitor) the following warning is written in the kern.log.Mar 20 16:29:08 impetus kernel: [19386.785229] WARNING: CPU: 3 PID: 11232 at /build/linux-_Kv5oI/linux-4.2.0/drivers/gpu/drm/i915/intel_pm.c:3404 skl_update_other_pipe_wm+0x1de/0x1f0 [i915]()Mar 20 16:29:08 impetus kernel: [19386.785235] WARN_ON(!wm_changed)Mar 20 16:29:08 impetus kernel: [19386.785240] Modules linked in: uas usb_storage rfcomm bnep hid_logitech_hidpp snd_hda_codec_hdmi cdc_mbim cdc_wdm cdc_ncm usbnet mii hid_logitech_dj uvcvideo btusb videobuf2_vmalloc btrtl videobuf2_memops btbcm btintel videobuf2_core v4l2_common usbhid videodev bluetooth hid media arc4 nls_iso8859_1 iwlmvm snd_hda_codec_realtek snd_hda_codec_generic intel_rapl mac80211 x86_pkg_temp_thermal intel_powerclamp coretemp kvm iwlwifi crct10dif_pclmul crc32_pclmul aesni_intel aes_x86_64 lrw gf128mul glue_helper ablk_helper cryptd snd_hda_intel cfg80211 snd_hda_codec snd_hda_core snd_hwdep input_leds snd_pcm serio_raw thinkpad_acpi nvram shpchp mei_me mei snd_seq_midi snd_seq_midi_event snd_rawmidi snd_seq snd_seq_device snd_timer snd soundcore joydev mac_hid parport_pc ppdev lp parport autofs4 i915 i2c_algo_bit drm_kms_helper drm psmouse e1000e ptp pps_core ahci libahci wmi videoMar 20 16:29:08 impetus kernel: [19386.785426] CPU: 3 PID: 11232 Comm: Xorg Tainted: G        W       4.2.0-34-generic #39-UbuntuMar 20 16:29:08 impetus kernel: [19386.785433] Hardware name: LENOVO 20F90042GE/20F90042GE, BIOS N1CET37W (1.05 ) 01/15/2016Mar 20 16:29:08 impetus kernel: [19386.785440]  0000000000000000 00000000a1f60d69 ffff8801fdedf518 ffffffff817ebed3Mar 20 16:29:08 impetus kernel: [19386.785451]  0000000000000000 ffff8801fdedf570 ffff8801fdedf558 ffffffff8107b986Mar 20 16:29:08 impetus kernel: [19386.785460]  ffff8801fdedf620 ffff8801fdedf6c4 ffff880214954000 ffff880214956000Mar 20 16:29:08 impetus kernel: [19386.785469] Call Trace:Mar 20 16:29:08 impetus kernel: [19386.785492]  [<ffffffff817ebed3>] dump_stack+0x45/0x57Mar 20 16:29:08 impetus kernel: [19386.785508]  [<ffffffff8107b986>] warn_slowpath_common+0x86/0xc0Mar 20 16:29:08 impetus kernel: [19386.785518]  [<ffffffff8107ba15>] warn_slowpath_fmt+0x55/0x70Mar 20 16:29:08 impetus kernel: [19386.785581]  [<ffffffffc0174b9e>] skl_update_other_pipe_wm+0x1de/0x1f0 [i915]Mar 20 16:29:08 impetus kernel: [19386.785627]  [<ffffffffc0174d6b>] skl_update_wm+0x1bb/0x740 [i915]Mar 20 16:29:08 impetus kernel: [19386.785700]  [<ffffffffc01c0a77>] ? gen9_read32+0xf7/0x2d0 [i915]Mar 20 16:29:08 impetus kernel: [19386.785760]  [<ffffffffc01a94c2>] ? i915_get_vblank_timestamp+0x62/0xa0 [i915]Mar 20 16:29:08 impetus kernel: [19386.785800]  [<ffffffffc01784be>] intel_update_watermarks+0x1e/0x30 [i915]Mar 20 16:29:08 impetus kernel: [19386.785871]  [<ffffffffc01dbd19>] intel_finish_crtc_commit+0x169/0x190 [i915]Mar 20 16:29:08 impetus kernel: [19386.785898]  [<ffffffffc014a8e3>] drm_atomic_helper_commit_planes_on_crtc+0x143/0x260 [drm_kms_helper]Mar 20 16:29:08 impetus kernel: [19386.785970]  [<ffffffffc01f51bb>] intel_atomic_commit+0x6b/0x100 [i915]Mar 20 16:29:08 impetus kernel: [19386.786030]  [<ffffffffc00e5dc7>] drm_atomic_commit+0x37/0x60 [drm]Mar 20 16:29:08 impetus kernel: [19386.786053]  [<ffffffffc014921f>] drm_atomic_helper_disable_plane+0xef/0x130 [drm_kms_helper]Mar 20 16:29:08 impetus kernel: [19386.786066]  [<ffffffff81212050>] ? poll_select_copy_remaining+0x140/0x140Mar 20 16:29:08 impetus kernel: [19386.786111]  [<ffffffffc00d59ba>] __setplane_internal+0x23a/0x2f0 [drm]Mar 20 16:29:08 impetus kernel: [19386.786122]  [<ffffffff81212050>] ? poll_select_copy_remaining+0x140/0x140Mar 20 16:29:08 impetus kernel: [19386.786163]  [<ffffffffc00d5b9b>] drm_mode_cursor_universal+0x12b/0x210 [drm]Mar 20 16:29:08 impetus kernel: [19386.786176]  [<ffffffff817f0a5f>] ? __ww_mutex_lock+0x5f/0xa0Mar 20 16:29:08 impetus kernel: [19386.786213]  [<ffffffffc00d5d01>] drm_mode_cursor_common+0x81/0x180 [drm]Mar 20 16:29:08 impetus kernel: [19386.786259]  [<ffffffffc00d9d20>] drm_mode_cursor_ioctl+0x50/0x70 [drm]Mar 20 16:29:08 impetus kernel: [19386.786288]  [<ffffffffc00ca505>] drm_ioctl+0x125/0x610 [drm]Mar 20 16:29:08 impetus kernel: [19386.786329]  [<ffffffffc00d9cd0>] ? drm_mode_setcrtc+0x500/0x500 [drm]Mar 20 16:29:08 impetus kernel: [19386.786341]  [<ffffffff81211375>] do_vfs_ioctl+0x295/0x480Mar 20 16:29:08 impetus kernel: [19386.786354]  [<ffffffff810885a1>] ? __set_task_blocked+0x41/0xa0Mar 20 16:29:08 impetus kernel: [19386.786364]  [<ffffffff812115d9>] SyS_ioctl+0x79/0x90Mar 20 16:29:08 impetus kernel: [19386.786372]  [<ffffffff8108b25e>] ? SyS_rt_sigprocmask+0x8e/0xc0Mar 20 16:29:08 impetus kernel: [19386.786380]  [<ffffffff817f2cf2>] entry_SYSCALL_64_fastpath+0x16/0x75I found the following question concerning a similar issue. However, the answer is rather disappointing and relatively useless.Here are my specs (Lenovo Thinkpad T460s):Processor:  4x Intel(R) Core(TM) i5-6200U CPU @ 2.30GHzGraphics:   Intel HD Graphics 520OS: Ubuntu 15.10 (4.2.0-34-generic #39-Ubuntu) / Unityglxinfo gives the following output:$ glxinfo[...]OpenGL vendor string: Intel Open Source Technology CenterOpenGL renderer string: Mesa DRI Intel(R) Skylake ULT GT2 OpenGL core profile version string: 3.3 (Core Profile) Mesa 11.0.2OpenGL core profile shading language version string: 3.30[...]Questions:Is the described issue a real problem? (apart from the excessive log entries)How can I fix this issue?Please do not hesitate to ask if you need further information
Strange warnings when cursor moves from one monitor to the other
ubuntu;x11;intel graphics;unity
Had the same problem with Intel Skylake ID.The problem was that the driver was not supportet ib 4.2 Kernel version. I updated to 4.5 and it works.Hope it helps.