TIP Activating wheelmouse support in Xorg

From Gentoo Linux Wiki

XOrg Index

Configuration

HIDevices

Fonts

Video Cards

Monitors

[edit] Introduction

If you've got a wheel mouse, it may not scroll when you move the mousewheel up and down by default. This little tip will get it going.

[edit] Xorg

Add the following line to the mouse section:

   Option      "ZAxisMapping" "4 5"

The section should now look something like this:

Section "InputDevice"
   Identifier  "Mouse1"
   Driver      "mouse"
   Option      "Protocol"     "IMPS/2"
   Option      "Device"       "/dev/mouse" # Usualy "/dev/psaux" with PS/2 mice and "dev/input/mice" with USB mice
   Option      "ZAxisMapping" "4 5"
EndSection

Then restart Xorg.

[edit] Kernel Support

If you have a USB mouse don't forget to enable the Open- and/or Universal Host Controller Driver in your kernel (PS/2 mice have no issues):

Device Drivers  --->
  USB support  --->
    ---   USB Host Controller Drivers
    <*>   OHCI HCD support
    <*>   UHCI HCD (most Intel and VIA) support

Sometimes even if you choose the wrong one or both your mouse might work exept for the scroll-wheel.