A few years ago, I got some cheap 27″ korean display (strongly influenced by this). Getting it to work properly with Xorg was not straightforward due to some corrupted EDID. I’m not sure where I got the original instructions from (might be there). I suspect that this record might come by handy when switching to wayland…

Anyway, I ended up with:

$ cat /etc/X11/xorg.conf.d/30-screen.conf
Section "Screen"
  Identifier "Screen0"
  Device "My GPU"
  Monitor "QHD270"
  DefaultDepth 24
  Option "CustomEDID" "DFP:/etc/X11/shimian-edid.bin"
  SubSection "Display"
  Depth 24
  EndSubSection
EndSection

and:

$ hexdump shimian-edid.bin
0000000 ff00 ffff ffff 00ff 6204 049b 0000 0000
0000010 1528 0301 3ca5 7822 6f22 a7b1 4c55 259e
0000020 500c 0054 0000 0101 0101 0101 0101 0101
0000030 0101 0101 0101 5e56 a000 a0a0 5029 2030
0000040 0035 5055 0021 1a00 0000 fc00 5100 4448
0000050 3732 0a30 2020 2020 2020 0000 fc00 0a00
0000060 2020 2020 2020 2020 2020 2020 0000 fc00
0000070 0a00 2020 2020 2020 2020 2020 2020 7e00
0000080 000a                                   
0000081

with a copy of the file available here.