To set up 1920x1200 resolution for XFree86, you will need to edit the XFree86 configuration file and add a new "ModeLine" entry for the desired resolution.
Here are the steps to set up 1920x1200 resolution for XFree86:
Determine the refresh rate of your display. You can usually find this information in the display's documentation or by using a tool such as "gtf" (part of the XFree86 package).
Open the XFree86 configuration file in a text editor. The location of the configuration file may vary depending on your system, but it is typically located at "/etc/X11/XF86Config" or "/etc/X11/xorg.conf".
Locate the "Monitor" section of the configuration file. This section should contain a "HorizSync" and "VertRefresh" option that specify the supported refresh rates of your display.
Add a new "ModeLine" entry to the "Monitor" section for the desired resolution and refresh rate. The "ModeLine" entry should have the following format:
ModeLine "1920x1200" 154 1920 1968 2000 2080 1200 1203 1209 1235Sourcww:ew.lautturi.com
Replace "1920x1200" with the desired resolution and "154" with the refresh rate determined in step 1. The other values specify timings for the display.
With these changes, XFree86 should be able to use the 1920x1200 resolution on your display. You can use the "xrandr" command to verify that the new resolution is available and to switch to it.
Note: The exact steps for setting up a custom resolution for XFree86 may vary depending on your system and display. It is a good idea to consult the documentation for your display and XFree86 for more detailed instructions.