Edit: Upgrading kernel to 4.11-rc2 solved the issue.
I have a brand new installation of Ubuntu Gnome on Lenovo Thinkpad L460. Can't seem to connect an external display to 4K mode via DP. FullHD and WQHD seem to work.
Someone suggested trying to install 4.4.8-040408-generic. Didn't work. Also installed intel-microcode proprietary drivers.
When I try to up the resolution to 4K from the displays screen,the monitor gets disabled. The following is printed to syslog:
Sep 7 10:46:10 juho-ThinkPad-L460 wpa_supplicant[2686]: wlp3s0: Failed to initiate sched scan
Sep 7 10:46:10 juho-ThinkPad-L460 /usr/lib/gdm3/gdm-x-session[3011]: (II) intel(0): resizing framebuffer to 3840x3240
Sep 7 10:46:10 juho-ThinkPad-L460 /usr/lib/gdm3/gdm-x-session[3011]: (II) intel(0): switch to mode 3840x2160@60.0 on DP1 using pipe 0, position (0, 0), rotation normal, reflection none
Sep 7 10:46:10 juho-ThinkPad-L460 /usr/lib/gdm3/gdm-x-session[3011]: (EE) intel(0): failed to set mode: Numerical result out of range [34]
Sep 7 10:46:10 juho-ThinkPad-L460 gnome-session[3027]: Window manager warning: Configuring CRTC 63 with mode 226 (3840 x 2160 @ 59,996624) at position 0, 0 and transform 0 failed
Sep 7 10:46:10 juho-ThinkPad-L460 /usr/lib/gdm3/gdm-x-session[3011]: (II) intel(0): switch to mode 1920x1080@60.0 on eDP1 using pipe 1, position (1920, 2160), rotation normal, reflection none
Edit: Here's the full journalctl output after attempting 4K in displays-config and pressing restore after.
syys 13 10:05:43 juho-ThinkPad-L460 /usr/lib/gdm3/gdm-x-session[2928]: (II) intel(0): resizing framebuffer to 5760x2160
syys 13 10:05:44 juho-ThinkPad-L460 /usr/lib/gdm3/gdm-x-session[2928]: (II) intel(0): switch to mode 1920x1080@60.0 on eDP1 using pipe 1, position (0, 0), rotation normal, reflection none
syys 13 10:05:45 juho-ThinkPad-L460 /usr/lib/gdm3/gdm-x-session[2928]: (II) intel(0): switch to mode 3840x2160@60.0 on DP1 using pipe 0, position (1920, 0), rotation normal, reflection none
syys 13 10:05:45 juho-ThinkPad-L460 /usr/lib/gdm3/gdm-x-session[2928]: (EE) intel(0): failed to set mode: Numerical result out of range [34]
syys 13 10:05:45 juho-ThinkPad-L460 gnome-session[2944]: Window manager warning: Configuring CRTC 63 with mode 226 (3840 x 2160 @ 59,996624) at position 1920, 0 and transform 0 failed
syys 13 10:05:51 juho-ThinkPad-L460 /usr/lib/gdm3/gdm-x-session[2928]: (II) intel(0): resizing framebuffer to 4480x1440
syys 13 10:05:51 juho-ThinkPad-L460 /usr/lib/gdm3/gdm-x-session[2928]: (II) intel(0): switch to mode 1920x1080@60.0 on eDP1 using pipe 0, position (0, 0), rotation normal, reflection none
syys 13 10:05:52 juho-ThinkPad-L460 kernel: ------------[ cut here ]------------
syys 13 10:05:52 juho-ThinkPad-L460 kernel: WARNING: CPU: 2 PID: 2930 at /home/kernel/COD/linux/drivers/gpu/drm/i915/intel_pm.c:3597 skl_update_other_pipe_wm+0x1de/0x1f0 [i915]()
syys 13 10:05:52 juho-ThinkPad-L460 kernel: WARN_ON(!wm_changed)
syys 13 10:05:52 juho-ThinkPad-L460 kernel: Modules linked in:
syys 13 10:05:52 juho-ThinkPad-L460 kernel: snd_seq_dummy rfcomm bnep snd_hda_codec_hdmi intel_rapl x86_pkg_temp_thermal intel_powerclamp coretemp snd_hda_codec_realtek snd_hda_codec_generic kvm arc4 binfmt_mis
syys 13 10:05:52 juho-ThinkPad-L460 kernel: mei snd_seq_device snd_timer snd soundcore mac_hid tpm_crb parport_pc ppdev lp parport autofs4 hid_generic usbhid hid rtsx_pci_sdmmc i915 e1000e ptp pps_core psmouse
syys 13 10:05:52 juho-ThinkPad-L460 kernel: CPU: 2 PID: 2930 Comm: Xorg Tainted: G W 4.4.8-040408-generic #201604200335
syys 13 10:05:52 juho-ThinkPad-L460 kernel: Hardware name: LENOVO 20FU002DMS/20FU002DMS, BIOS R08ET42W (1.16 ) 06/17/2016
syys 13 10:05:52 juho-ThinkPad-L460 kernel: 0000000000000286 00000000592b92cf ffff88030df67810 ffffffff813cee93
syys 13 10:05:52 juho-ThinkPad-L460 kernel: ffff88030df67858 ffffffffc0273c70 ffff88030df67848 ffffffff8107fe12
syys 13 10:05:52 juho-ThinkPad-L460 kernel: ffff88030df6797c ffff88003541e000 ffff88003541f000 0000000000000000
syys 13 10:05:52 juho-ThinkPad-L460 kernel: Call Trace:
syys 13 10:05:52 juho-ThinkPad-L460 kernel: [<ffffffff813cee93>] dump_stack+0x63/0x90
syys 13 10:05:52 juho-ThinkPad-L460 kernel: [<ffffffff8107fe12>] warn_slowpath_common+0x82/0xc0
syys 13 10:05:52 juho-ThinkPad-L460 kernel: [<ffffffff8107feac>] warn_slowpath_fmt+0x5c/0x80
syys 13 10:05:52 juho-ThinkPad-L460 kernel: [<ffffffffc01add9e>] skl_update_other_pipe_wm+0x1de/0x1f0 [i915]
syys 13 10:05:52 juho-ThinkPad-L460 kernel: [<ffffffffc01ae002>] skl_update_wm+0x252/0x7d0 [i915]
syys 13 10:05:52 juho-ThinkPad-L460 kernel: [<ffffffffc01f6ee4>] ? gen9_read32+0x124/0x2f0 [i915]
syys 13 10:05:52 juho-ThinkPad-L460 kernel: [<ffffffffc01b266e>] intel_update_watermarks+0x1e/0x30 [i915]
syys 13 10:05:52 juho-ThinkPad-L460 kernel: [<ffffffffc0217b77>] intel_atomic_commit+0x427/0x6f0 [i915]
syys 13 10:05:52 juho-ThinkPad-L460 kernel: [<ffffffffc007bb17>] drm_atomic_commit+0x37/0x60 [drm]
syys 13 10:05:52 juho-ThinkPad-L460 kernel: [<ffffffffc00ee5a6>] drm_atomic_helper_set_config+0x76/0xb0 [drm_kms_helper]
syys 13 10:05:52 juho-ThinkPad-L460 kernel: [<ffffffffc006ad22>] drm_mode_set_config_internal+0x62/0x100 [drm]
syys 13 10:05:52 juho-ThinkPad-L460 kernel: [<ffffffffc006f242>] drm_mode_setcrtc+0x3d2/0x4f0 [drm]
syys 13 10:05:52 juho-ThinkPad-L460 kernel: [<ffffffffc0060722>] drm_ioctl+0x152/0x540 [drm]
syys 13 10:05:52 juho-ThinkPad-L460 kernel: [<ffffffffc006ee70>] ? drm_mode_setplane+0x1b0/0x1b0 [drm]
syys 13 10:05:52 juho-ThinkPad-L460 kernel: [<ffffffff8121d108>] do_vfs_ioctl+0x298/0x480
syys 13 10:05:52 juho-ThinkPad-L460 kernel: [<ffffffff8108ceb1>] ? __set_task_blocked+0x41/0xa0
syys 13 10:05:52 juho-ThinkPad-L460 kernel: [<ffffffff8108f846>] ? __set_current_blocked+0x36/0x60
syys 13 10:05:52 juho-ThinkPad-L460 kernel: [<ffffffff8121d369>] SyS_ioctl+0x79/0x90
syys 13 10:05:52 juho-ThinkPad-L460 kernel: [<ffffffff8108fafe>] ? SyS_rt_sigprocmask+0x8e/0xc0
syys 13 10:05:52 juho-ThinkPad-L460 kernel: [<ffffffff81806276>] entry_SYSCALL_64_fastpath+0x16/0x75
syys 13 10:05:52 juho-ThinkPad-L460 kernel: ---[ end trace 972d78447654bc07 ]---
syys 13 10:05:52 juho-ThinkPad-L460 /usr/lib/gdm3/gdm-x-session[2928]: (II) intel(0): switch to mode 2560x1440@60.0 on DP1 using pipe 1, position (1920, 0), rotation normal, reflection none
syys 13 10:05:53 juho-ThinkPad-L460 kernel: snd_hda_codec_hdmi hdaudioC0D2: HDMI: ELD buf size is 0, force 128
syys 13 10:05:53 juho-ThinkPad-L460 kernel: snd_hda_codec_hdmi hdaudioC0D2: HDMI: invalid ELD data byte 0
syys 13 10:05:53 juho-ThinkPad-L460 /usr/lib/gdm3/gdm-x-session[2928]: (II) intel(0): resizing framebuffer to 1920x1080
syys 13 10:05:53 juho-ThinkPad-L460 /usr/lib/gdm3/gdm-x-session[2928]: (II) intel(0): resizing framebuffer to 4480x1440
syys 13 10:05:53 juho-ThinkPad-L460 /usr/lib/gdm3/gdm-x-session[2928]: (II) intel(0): switch to mode 2560x1440@60.0 on DP1 using pipe 0, position (1920, 0), rotation normal, reflection none
syys 13 10:05:53 juho-ThinkPad-L460 wpa_supplicant[2706]: wlp3s0: CTRL-EVENT-SCAN-FAILED ret=-16 retry=1
syys 13 10:05:53 juho-ThinkPad-L460 /usr/lib/gdm3/gdm-x-session[2928]: (II) intel(0): switch to mode 1920x1080@60.0 on eDP1 using pipe 1, position (0, 0), rotation normal, reflection none