If you've just upgraded your FreeBSD and your mouse is not working under X.org (and you use FreeBSD 7.2 or FreeBSD 8.0) here is what you must do to fix the problem.

Step 1. Disable moused daemon, enable hald and other daemons
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Remove from rc.conf lines regarding mused and add the following lines to /etc/rc.conf

moused_enable="NO"
moused_nondefault_enable="NO"

dbus_enable="YES"
polkitd_enable="YES"
hald_enable="YES"


Step 2. Remove keyboard and mouse entries from /etc/X11/xorg.conf
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Remove all entries regarding keyboard and mouse from /etc/X11/xorg.conf or remove /etc/X11/xorg.conf completly.
New version of Xorg autodetects mousea, keyboard and video. If you video is not detected properly or you want to change screen resolution you might need a xorg.conf file.


Step 3. Compile xorg without hald
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To compile from ports xorg without hald:

cd /usr/ports/x11-servers/xorg-server
make clean
make config

Then, uncheck hald.

make
make deinstall
make reinstall

That's all. Now your mouse will work.