Note that compared to #1559308 , connecting the same monitor via the HDMI port on the laptop running 4.4.0-28-generic does seem to work fine: There's still some stuff in dmesg when using HDMI as well: snd_hda_codec_hdmi hdaudioC0D2: HDMI: ELD buf size is 0, force 128 snd_hda_codec_hdmi hdaudioC0D2: HDMI: invalid ELD data byte 0 ------------[ cut here ]------------ WARNING: CPU: 1 PID: 1080 at /build/linux-BvkamA/linux-4.4.0/ubuntu/i915/intel_pm.c:3586 skl_update_other_pipe_wm+0x16c/0x180 [i915_bpo]() WARN_ON(!wm_changed) Modules linked in: ctr ccm rfcomm bnep arc4 snd_soc_skl snd_soc_skl_ipc snd_hda_ext_core intel_rapl x86_pkg_temp_thermal snd_soc_sst_ipc intel_powerclamp coretemp snd_soc_sst_dsp snd_hda_codec_hdmi snd_soc_core kvm_intel snd_compress ac97_bus snd_pcm_dmaengine snd_hda_codec_realtek kvm dw_dmac_core snd_hda_codec_generic input_leds snd_hda_intel irqbypass iwlmvm uvcvideo snd_hda_codec videobuf2_vmalloc videobuf2_memops mac80211 snd_hda_core videobuf2_v4l2 videobuf2_core v4l2_common snd_hwdep joydev serio_raw snd_pcm videodev btusb media btrtl thinkpad_acpi cdc_ether btbcm option iwlwifi nvram usbnet usb_wwan usbserial btintel mii rtsx_pci_ms snd_seq_midi bluetooth memstick snd_seq_midi_event cfg80211 snd_rawmidi mei_me mei snd_seq shpchp snd_seq_device snd_timer snd soundcore mac_hid parport_pc ppdev lp parport autofs4 btrfs xor raid6_pq drbg ansi_cprng algif_skcipher af_alg dm_crypt rtsx_pci_sdmmc i915_bpo crct10dif_pclmul crc32_pclmul aesni_intel intel_ips i2c_algo_bit aes_x86_64 drm_kms_helper lrw gf128mul glue_helper ablk_helper syscopyarea cryptd sysfillrect sysimgblt fb_sys_fops e1000e ahci drm psmouse ptp rtsx_pci pps_core libahci wmi video fjes CPU: 1 PID: 1080 Comm: Xorg Not tainted 4.4.0-28-generic #47-Ubuntu Hardware name: LENOVO 20F6007RGE/20F6007RGE, BIOS R02ET48W (1.21 ) 06/01/2016 0000000000000286 000000009c6cf672 ffff88040dfa39a8 ffffffff813eb1a3 ffff88040dfa39f0 ffffffffc0373c98 ffff88040dfa39e0 ffffffff81081102 ffff88040fc7c000 ffff880409629d9c ffff88040fc7b000 ffff880409020b78 Call Trace: [] dump_stack+0x63/0x90 [] warn_slowpath_common+0x82/0xc0 [] warn_slowpath_fmt+0x5c/0x80 [] skl_update_other_pipe_wm+0x16c/0x180 [i915_bpo] [] skl_update_wm+0x186/0x5f0 [i915_bpo] [] ? intel_display_power_put+0xd0/0x130 [i915_bpo] [] intel_update_watermarks+0x1e/0x30 [i915_bpo] [] intel_atomic_commit+0x485/0xdc0 [i915_bpo] [] ? drm_atomic_check_only+0x18e/0x590 [drm] [] drm_atomic_commit+0x37/0x60 [drm] [] drm_atomic_helper_set_config+0x76/0xb0 [drm_kms_helper] [] ? drm_modeset_lock_all_ctx+0x9a/0xb0 [drm] [] drm_mode_set_config_internal+0x62/0x100 [drm] [] drm_mode_setcrtc+0x3d2/0x4f0 [drm] [] drm_ioctl+0x152/0x540 [drm] [] ? drm_mode_setplane+0x1b0/0x1b0 [drm] [] do_vfs_ioctl+0x29f/0x490 [] ? __sys_recvmsg+0x80/0x90 [] SyS_ioctl+0x79/0x90 [] entry_SYSCALL_64_fastpath+0x16/0x71 ---[ end trace a13f8ffdea74aa69 ]---