suckless Second Display

A 4K screen stacked ontop of my T14s as my window to the world

Published: Friday, Sep 3, 2021 Last modified: Monday, Apr 8, 2024

The LG 27UN880-B is a 4K USB-C screen I bought to improve my desktop setup.

LG 27UN880-B

I find I get best results when I connect via DisplayPort or USB-C which also appears in xrandr as DisplayPort-1.

USB-C connections on a T14s
ins)[hendry@t14s ~]$ xrandr --auto --output DisplayPort-1 --above eDP
(ins)[hendry@t14s ~]$ xrandr
Screen 0: minimum 320 x 200, current 1920 x 1080, maximum 16384 x 16384
eDP connected primary 1920x1080+0+0 (normal left inverted right x axis y axis) 309mm x 174mm
   1920x1080     60.05*+
   1680x1050     60.05
   1280x1024     60.05
   1440x900      60.05
   1280x800      60.05
   1280x720      60.05
   1024x768      60.05
   800x600       60.05
   640x480       60.05
HDMI-A-0 disconnected (normal left inverted right x axis y axis)
DisplayPort-0 disconnected (normal left inverted right x axis y axis)
DisplayPort-1 connected (normal left inverted right x axis y axis)
   3840x2160     60.00 +  30.00
   2560x1440     59.95
   1920x1200     60.00
   1920x1080     60.00    59.94
   1600x1200     60.00
   1680x1050     60.00
   1600x900      60.00
   1280x1024     60.02
   1440x900      60.00
   1280x800      59.81
   1280x720      60.00    59.94
   1024x768      60.00
   800x600       60.32
   720x480       60.00    59.94
   640x480       60.00    59.94

Using udevadm monitor 2>&1 | tee LG-27UN880-B-with-inputs-udev.txt, I am not sure which event to hinge a rule off:


Since the font appears small on 4K, should I be scaling the screen?

Or should I just get into the habit of punching Ctrl-Plus to resize my browser windows or terminals?


Numpad doesn’t work in Linux.


(ins)[hendry@t14s]$ xlayoutdisplay
eDP active 31cm/17cm 1920x1080+0+2160 60Hz
*+!1920x1080 60Hz
   1680x1050 60Hz
   1280x1024 60Hz
   1440x900 60Hz
   1280x800 60Hz
   1280x720 60Hz
   1024x768 60Hz
   800x600 60Hz
   640x480 60Hz
HDMI-A-0 disconnected
DisplayPort-0 disconnected
DisplayPort-1 active 60cm/34cm 3840x2160+0+0 60Hz
*+!3840x2160 60Hz
   3840x2160 30Hz
   2560x1440 60Hz
   1920x1200 60Hz
   1920x1080 60Hz
   1920x1080 60Hz
   1600x1200 60Hz
   1680x1050 60Hz
   1600x900 60Hz
   1280x1024 60Hz
   1440x900 60Hz
   1280x800 60Hz
   1280x720 60Hz
   1280x720 60Hz
   1024x768 60Hz
   800x600 60Hz
   720x480 60Hz
   720x480 60Hz
   640x480 60Hz
   640x480 60Hz
*current +preferred !optimal

laptop lid open or not present

calculated DPI 156 for output eDP

xrandr \
 --dpi 156 \
 --output eDP --mode 1920x1080 --rate 60 --pos 0x0 --primary \
 --output HDMI-A-0 --off \
 --output DisplayPort-0 --off \
 --output DisplayPort-1 --mode 3840x2160 --rate 60 --pos 1920x0

echo "Xft.dpi: 156" | xrdb -merge


Not sure why I have to run xrandr --output DisplayPort-0 --set TearFree on, but it seems to help.

SystemD interface for controlling Power options

(ins)[hendry@t14s ~]$ grep -v "#" /etc/systemd/logind.conf



MacOS the server

Due to MacOS secure keyboard, the keyboard is not shared to my Archlinux machine intermittedly. This makes running barrier on MacOS unworkable.

Archlinux as the barrier server

I can feel the lag from to time.

Copy and paste for images does not work

Clipboard does feel a bit cripped, like I can’t see to paste without formatting.