It is possible you will need to coax the preferred mode with the addition of a modeline in your modes section. Now you can generate modelines from a CLI utility called gtf. For example, to get a modeline for 1366x768 @ 60Hz:
gtf 1366 768 60
1368x768 @ 60.00 Hz (GTF) hsync: 47.70 kHz; pclk: 85.86 MHz
Modeline “1368x768_60.00” 85.86 1368 1440 1584 1800 768 769 772 795 -HSync +Vsync
Before we go any further, you will need to edit your /etc/X11/xorg.conf file as root. I prefer to use a terminal-based editor like nano or pico, but there are several others for you to choose from. Make sure you backup your current xorg.conf first, so that you can reinstate it if you make a typo, or delete something accidentally. You can do this with something like:
cp /etc/X11/xorg.conf /etc/X11/xorg.working
Now you can add that modeline to your modes section:
Section “Modes”
Identifier “Modes[0]”
Modeline “1368x768” 85.86 1368 1440 1584 1800 768 769 772 795 -HSync +Vsync
EndSection
Note: I edited the “1368x768” label to match exactly with your preferred mode in monitor section.
These days, modelines are normally derived automatically using the EDID info from your display device. It doesn’t always work properly with some hardware, hence the need to add modelines. In addition to this, it is often necessary to force Xorg to use the modeline by adding a line to ignore EDID in the device section like this:
Section “Device”
…
Option “IgnoreEDID” “True”
EndSection
Another option that can also be used is
Option “NoDDC” “TRUE”
However, I’m not sure if they are both necessary. (Try adding it if the above isn’t enough).
I also note you have a large virtual screen size configured in your screen section.
SubSection “Display”
Depth 24
Modes “1366x768” “1360x768” “1280x768” “1280x720” “1024x768” “1280x600” “1024x600” “800x600” “768x576” “640x480”
Virtual 3840 1200
If this is not intended or required, then I would remove the ‘Virtual 3840 1200’ entry.
