Comment 1 for bug 586402

Relevant part when the scrolling is working:

...
(II) config/udev: Adding input device PS/2 Mouse (/dev/input/event8)
(**) PS/2 Mouse: Applying InputClass "evdev pointer catchall"
(**) PS/2 Mouse: always reports core events
(**) PS/2 Mouse: Device: "/dev/input/event8"
(II) PS/2 Mouse: Found 3 mouse buttons
(II) PS/2 Mouse: Found relative axes
(II) PS/2 Mouse: Found x and y relative axes
(II) PS/2 Mouse: Configuring as mouse
(**) PS/2 Mouse: YAxisMapping: buttons 4 and 5
(**) PS/2 Mouse: EmulateWheelButton: 4, EmulateWheelInertia: 10, EmulateWheelTimeout: 200
(II) XINPUT: Adding extended input device "PS/2 Mouse" (type: MOUSE)
(II) PS/2 Mouse: initialized for relative axes.
(II) config/udev: Adding input device PS/2 Mouse (/dev/input/mouse1)
(II) No input driver/identifier specified (ignoring)
(II) config/udev: Adding input device AlpsPS/2 ALPS GlidePoint (/dev/input/event11)
(**) AlpsPS/2 ALPS GlidePoint: Applying InputClass "evdev pointer catchall"
(**) AlpsPS/2 ALPS GlidePoint: Applying InputClass "evdev touchpad catchall"
(**) AlpsPS/2 ALPS GlidePoint: Applying InputClass "touchpad catchall"
(II) LoadModule: "synaptics"
(II) Loading /usr/lib/xorg/modules/input/synaptics_drv.so
(II) Module synaptics: vendor="X.Org Foundation"
 compiled for 1.7.6, module version = 1.2.2
 Module class: X.Org XInput Driver
 ABI class: X.Org XInput driver, version 7.0
(II) Synaptics touchpad driver version 1.2.2
(**) Option "Device" "/dev/input/event11"
(II) AlpsPS/2 ALPS GlidePoint: x-axis range 0 - 1023
(II) AlpsPS/2 ALPS GlidePoint: y-axis range 0 - 767
(II) AlpsPS/2 ALPS GlidePoint: pressure range 0 - 127
(II) AlpsPS/2 ALPS GlidePoint: finger width range 0 - 0
(II) AlpsPS/2 ALPS GlidePoint: buttons: left right middle
(--) AlpsPS/2 ALPS GlidePoint: touchpad found
(**) AlpsPS/2 ALPS GlidePoint: always reports core events
(II) XINPUT: Adding extended input device "AlpsPS/2 ALPS GlidePoint" (type: TOUCHPAD)
(**) AlpsPS/2 ALPS GlidePoint: (accel) keeping acceleration scheme 1
(**) AlpsPS/2 ALPS GlidePoint: (accel) acceleration profile 0
(**) AlpsPS/2 ALPS GlidePoint: (accel) acceleration factor: 2.000
(**) AlpsPS/2 ALPS GlidePoint: (accel) acceleration threshold: 4
(--) AlpsPS/2 ALPS GlidePoint: touchpad found
(II) config/udev: Adding input device AlpsPS/2 ALPS GlidePoint (/dev/input/mouse2)
(II) No input driver/identifier specified (ignoring)
....

Note that some kind of PS/2 mouse is detected when it is working.