synaptics touchpad. reconnect not supported

[Paul Vojta]

On Mon, Jun 30, 2008 at 04:26:25PM +0200, Nicolò Chieffo wrote:
> I have a laptop that has a problem with the touchpad: if hitting a key
> combination the synaptics touchpad loses the synchronization and it
> reconnects.
> this is the log output in kern.log:
> 
> psmouse.c: TouchPad at isa0060/serio1/input0 lost sync at byte 1
> psmouse.c: TouchPad at isa0060/serio1/input0 lost sync at byte 1
> psmouse.c: TouchPad at isa0060/serio1/input0 lost sync at byte 1
> psmouse.c: TouchPad at isa0060/serio1/input0 lost sync at byte 1
> psmouse.c: TouchPadat isa0060/serio1/input0 lost sync at byte 1
> psmouse.c: issuing reconnect request
> Synaptics Touchpad, model: 1, fw: 6.3, id: 0x1a0b1, caps: 0xa04713/0x200000
> input: SynPS/2 Synaptics TouchPad as /class/input/input19
> 
> The windows driver is smarter, and can handle device disconnections,
> while the synaptics xorg driver (I have version 0.14.6) once the
> device is disconnected, it treats it as a normal mouse after the
> reconnection (no scroll, different acceleration, no finger
> combinations,...)

The problem is that the touchpad is getting assigned a different number
after reconnecting.

This can be fixed by the following (suggested by Stefan Monnier):

1 - use a udev rule so that the touchpad is always available as
    /dev/input/touchpad:

    kernel=="event*", DRIVERS=="synaptics-usb", SYMLINK+="input/touchpad"

2 - Force the synaptics driver to use that special device name:

        Option          "Device"        "/dev/input/touchpad"

You might need to adapt the DRIVERS line if your touchpad is not USB.

--Paul Vojta, vojta at math.berkeley.edu