From DSL Wiki
This script, xsetup.sh, allows for simple and easy configuration of DSL's default X servers, Xvesa and Xfbdev. Unlike Xfree86, these servers do not use an external configuration file, such as XF86Config-4. Instead they are completely controlled by runtime flags in the .xserverrc file, located in the user's /home directory.
Xsetup.sh can be made to run automatically from the Boot: prompt with the "xsetup" cheatcode.
X Setup Demonstration
This is a demonstration of how to set up a system using a two-button serial mouse on /dev/ttyS0 (DOS port com1) using Xvesa at 800x600 resolution with 16bit color depth.
First, at the Boot: prompt, type "dsl xsetup" along with any other desired cheatcodes.
After the usual DSL loading sequence,
you will be met by this screen.
Make sure that Xvesa is selected, and press Enter.
Say "no" to the questions on the next two screens, since we are not using a USB mouse, or an IMPS/2 mouse. The IMPS/2 protocol is commonly used for an "Intellimouse", which is most mice that have a scroll wheel on top.
The next screen allows selection of the mouse port. Choose com1, since the mouse is attached to /dev/ttyS0.
Select 2 buttons...
Then select the resolution. For this example, we are choosing 800x600.
Next is the color depth. We chose 16bit color here.
We do not want to set our own DPI. The server automatically sets it properly.
Lastly, select your keyboard layout. We used the default US keyboard here.
Press enter, and X is set up! It should start automatically, if you did "dsl xsetup" from the boot: prompt. If you ran xsetup.sh from bash, exit X if needed and type "startx" to start the server.