Touchpad/Testing

Touchpad calibration and testing is a complex area, not very well documented in the industry. This page collects useful information when testing and debugging touchpads.

OLPC has shipped 3 touchpads

• ALPS (in XO-1 CL1 model)
• Synaptics (in XO-1 CL1A model, XO-1.5, XO-1.75)
• Sentelic AVC (in XO-1 CL1A model, XO-1.5, XO-1.75)

Right after boot, use "dmesg | grep -i psmouse" to see what protocol is in use. This usually reveals the tp in use.

Tests

Standing finger

• Place your finger in one spot, keep it there for a long time. The pointer should not move.

Variables

• Dirty power --
• Approach speed
• Firmness of touch
• Hand placement
• Lap vs table
• Humidity and temperature
• Wet finger
• Finger size
• Dust
• User variation