See xorg for configuring the mouse in graphic mode.
To test a mouse in text mode cat /dev/input/mouse0 reads from the mouse and shows that it is alive Ctrl C quites it.
If the /dev
file not exist. Check if CONFIG_INPUT_MOUSEDEV is set in the kernel
For having the mouse in text mode use gpm
gpm -m /dev/input/mice
For OpenRC
/etc/init.d/gpm start and rc-update add gpm default
If it does not work under the xserver Ctrl Alt F1 to open a text screen and start a text application that has mouse support as mc Alt F7 brings you back to the xserver
Type man gpm to get info about the options and mev to see the mouse events.