Ubuntu Natty: Fixing the "mouse" on HP 2540p

Update: This fix is now documented in the Ubuntu Wiki

After upgrading to Natty alpha 2 clicking left+right mouse no longer worked as middle mouse button (also known as Emulate3Buttons).

Since version 10.04 (and for real since 10.10) Ubuntu no longer sports a xorg.conf file; all configuration is done through udev and evdev – for some reason the “mouse” (track point) in my HP Elitebook 2540p is detected as a three button mouse

[    35.650] (**) PS/2 Generic Mouse: always reports core events
[    35.650] (**) PS/2 Generic Mouse: Device: "/dev/input/event8"
[    35.650] (--) PS/2 Generic Mouse: Found 3 mouse buttons
[    35.650] (--) PS/2 Generic Mouse: Found relative axes
[    35.650] (--) PS/2 Generic Mouse: Found x and y relative axes
[    35.650] (II) PS/2 Generic Mouse: Configuring as mouse

The fix is to add a couple of parameters to /usr/share/X11/xorg.conf.d/10-evdev.conf.

First, we make sure the file is not overwritten by package updates

$ sudo dpkg-divert --add --rename --divert /usr/share/X11/xorg.conf.d/10-evdev.conf.real /usr/share/X11/xorg.conf.d/10-evdev.conf<br /> $ sudo cp /usr/share/X11/xorg.conf.d/10-evdev.conf.real /usr/share/X11/xorg.conf.d/10-evdev.conf

Now, open /usr/share/X11/xorg.conf.d/10-evdev.conf and add the following lines to the section evdev pointer catchall

        Option "Emulate3Buttons" "True"
        Option "Emulate3Timeout" "50"

This will also add 3 button emulation for any external mouse added but I can live with that.