[sugar] Recalibrating the touchpad.

[Jim Gettys]

 As a capacitive sensor, when the environment changes, the capacitive
touchpad will need recalibration. The B2 and before touchpads do not
auto-calibrate.
 1) if you have your finger on the touchpad during power-on, you can
cause problems.
 2) the calibration may shift when you go to/from battery power, or
after resuming from suspend (not yet deployed).

To force a recalibration of the touchpad, you perform what we call the
"four finger salute".  To recalibrate, press all four keys at the
corners of the keyboard at the same time, pressing the "alt" key last,
while keeping your fingers off the touchpad.

BTest-3 and beyond will automatically recalibrate.  We received samples
of the BTest-3 touchpads late last week, and have installed several, and
are happy so far with their behavior.

Remember: please leave the (slightly off color) plastic sheet on the
touchpad; it does make the touchpads work much better.
                                      - Jim

-- 
Jim Gettys
One Laptop Per Child