Here is my original xrandr output. The resolution problem hapens on my laptop screen (eDP)
Screen 0: minimum 320 x 200, current 4800 x 1800, maximum 16384 x 16384
eDP connected 2880x1800+0+0 (normal left inverted right x axis y axis) 302mm x 189mm
2880x1800 90.00*+ 60.00
(used to be way more options than only this one)
HDMI-A-0 connected primary 1920x1080+2880+0 (normal left inverted right x axis y axis) 598mm x 336mm
1920x1080 60.00 + 74.97* 50.00 59.94
...
(pointless to show other options for this screen - no problem with this one)
Here are the commands I executed :
cvt 1920 1200 90 # I also tried every commands with 60Hz
# 1920x1200 89.91 Hz(CVT) hsync: 113.83 kHz; pclk: 300.50 MHz
Modeline "1920x1200_90.00" 300.50 1920 2072 2280 2640 1200 1203 1209 1266 -hsync +vsync
xrandr --newmode "1920x1200_90.00" 300.50 1920 2072 2280 2640 1200 1203 1209 1266 -hsync +vsync
xrandr --addmode eDP 1920x1200_90.00
After this command, the 1920x1200 option appeared in xrandr and in settings menu :
Screen 0: minimum 320 x 200, current 4800 x 1800, maximum 16384 x 16384
eDP connected 2880x1800+0+0 (normal left inverted right x axis y axis) 302mm x 189mm
2880x1800 90.00*+ 60.00
1920x1200_90.00 89.91 # new mode
HDMI-A-0 connected primary 1920x1080+2880+0 (normal left inverted right x axis y axis) 598mm x 336mm
1920x1080 60.00 + 74.97* 50.00 59.94
...
Then I switched mode by running this
xrandr --output eDP --mode 1920x1200_90.00
or by choosing this new mode in the settings options, my screen turns black every time.
Screen 0: minimum 320 x 200, current 4800 x 1200, maximum 16384 x 16384
eDP connected 1920x1200+0+0 (normal left inverted right x axis y axis) 302mm x 189mm
2880x1800 90.00 + 60.00
1920x1200_90.00 89.91* # the mode is selected
HDMI-A-0 connected primary 1920x1080+2880+0 (normal left inverted right x axis y axis) 598mm x 336mm
1920x1080 60.00 + 74.97* 50.00 59.94
...
I tried to reboot, but after each attempt the new mode is just gone after reboot.
Switching back to 2880x1800 60/90Hz makes the screen work again.
I noticed that after switching to the new mode, the screen settings looked a bit weird, they are spaced I'm not sure to understand why :
