Touchpad/tablet problem

Richard A. Smith richard at
Mon Dec 29 20:06:32 EST 2008

Greg Smith wrote:

> Hopefully one of the touchpad/firmware experts can give you a link to 
> how you can capture and use raw data generated by the touchpad.

The datasheet is here:

You want to put the touchpad into "Advanced Mode."  In this mode it will 
  generate resistive mode data.

Previous versions of the kernel driver supported operation in advanced 
mode.  I suggest you look at the git changelog for 
/drivers/input/mouse/olpc.c and find the patch where we switched from 
advanced mode back to mouse mode.  The driver prior to that patch will 
have all the info you need.

Be warned however that sometime in Jan/Feb the XO production line will 
switch to a Synaptics device rather than an ALPS device and the 
Synaptics device does _not_ have any resistive features.

Richard Smith  <richard at>
One Laptop Per Child

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