For a couple of years now I haven't been able to get my LG Flatron W2261VP to work as an external monitor for my ThinkPad T460s running Kubuntu (currently 18.04.3 with Kernel 4.15.0). It's connected through HDMI since the T460S doesn't have a VGA slot.
In the beginning, I plugged in the HDMI cable and the monitor was recognized in the system settings, but I couldn't turn it on. Every once in a while I tried again and sometimes the monitor didn't even appear in the system settings. Currently it does. But as soon as I plug in the cable, the system partly freezes/slows down and it's impossible to work, because the laptop monitor turns black every couple of seconds. The external monitor remains black and sometimes displays a messages about HDMI power saving mode.
I have been able to connect other external monitors through HDMI though. I also checked the cable with another machine. For a short time, when Kernel 4.10 was installed, the problem disappeared (see Can't get external monitor to work through HDMI (Thinkpad T460s, Kubuntu)).
I have also tried using the monitor with Live USB (both Ubuntu 18.04 and Kubuntu 18.04), but the problem is the same.
Any ideas for a solution? I attach some command results.
$ uname -rm
4.15.0-34-generic x86_64
$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 18.04.3 LTS
Release: 18.04
Codename: bionic
$ lspci -nnk | grep -i VGA -A2
00:02.0 VGA compatible controller [0300]: Intel Corporation Skylake GT2 [HD Graphics 520] [8086:1916] (rev 07)
Subsystem: Lenovo Skylake GT2 [HD Graphics 520] [17aa:2233]
Kernel driver in use: i915
$ sudo lshw -c video
*-display
Beschreibung: VGA compatible controller
Produkt: Skylake GT2 [HD Graphics 520]
Hersteller: Intel Corporation
Physische ID: 2
Bus-Informationen: pci@0000:00:02.0
Version: 07
Breite: 64 bits
Takt: 33MHz
Fähigkeiten: pciexpress msi pm vga_controller bus_master cap_list rom
Konfiguration: driver=i915 latency=0
Ressourcen: irq:124 memory:f0000000-f0ffffff memory:e0000000-efffffff ioport:e000(Größe=64) memory:c0000-dffff
$ xrandr
Screen 0: minimum 320 x 200, current 1920 x 1080, maximum 8192 x 8192
eDP-1 connected primary 1920x1080+0+0 (normal left inverted right x axis y axis) 310mm x 170mm
2560x1440 60.00 + 48.00 59.95
1920x1440 60.00
1856x1392 60.01
1792x1344 60.01
2048x1152 59.90 59.91
1920x1200 59.88 59.95
1920x1080 59.97* 59.96 59.93
1600x1200 60.00
1680x1050 59.95 59.88
1600x1024 60.17
1400x1050 59.98
1600x900 59.99 59.94 59.95 59.82
1280x1024 60.02
1440x900 59.89
1400x900 59.96 59.88
1280x960 60.00
1440x810 60.00 59.97
1368x768 59.88 59.85
1360x768 59.80 59.96
1280x800 59.99 59.97 59.81 59.91
1152x864 60.00
1280x720 60.00 59.99 59.86 59.74
1024x768 60.04 60.00
960x720 60.00
928x696 60.05
896x672 60.01
1024x576 59.95 59.96 59.90 59.82
960x600 59.93 60.00
960x540 59.96 59.99 59.63 59.82
800x600 60.00 60.32 56.25
840x525 60.01 59.88
864x486 59.92 59.57
800x512 60.17
700x525 59.98
800x450 59.95 59.82
640x512 60.02
720x450 59.89
700x450 59.96 59.88
640x480 60.00 59.94
720x405 59.51 58.99
684x384 59.88 59.85
680x384 59.80 59.96
640x400 59.88 59.98
576x432 60.06
640x360 59.86 59.83 59.84 59.32
512x384 60.00
512x288 60.00 59.92
480x270 59.63 59.82
400x300 60.32 56.34
432x243 59.92 59.57
320x240 60.05
360x202 59.51 59.13
320x180 59.84 59.32
DP-1 disconnected (normal left inverted right x axis y axis)
HDMI-1 disconnected (normal left inverted right x axis y axis)
DP-2 disconnected (normal left inverted right x axis y axis)
HDMI-2 connected (normal left inverted right x axis y axis)
1920x1080 59.93 + 60.00 60.00 50.00 59.94
1920x1080i 60.00 50.00 59.94
1680x1050 59.88
1280x1024 60.02
1280x960 60.00
1280x720 60.00 50.00 59.94
1024x768 60.00
800x600 60.32
720x576 50.00
720x480 60.00 59.94
640x480 60.00 59.94
This is the syslog from the moment I plug in the cable: https://paste.ubuntu.com/p/qtJJ8tzQ4K/
I have tried deleting ./local/share/kscreen as suggested here: https://bugs.kde.org/show_bug.cgi?id=353637 But that didn't help.
