Done during manufacturing. Calibration parameters are often stored in the I2C controller's non-volatile memory (EEPROM).
Driver architecture overview
and search for "Calibrate the screen for pen or touch input". kmdf hid minidriver for touch i2c device calibration
When processing multi-touch data over I2C, loop through every single active contact point tracking ID. Calibrate each pair of raw coordinates independently using the same transformation matrix before saving them to your structured output array. Power State Resets Done during manufacturing
#include <wdf.h> #include <hid.h>
Upper filter on top of HIDI2C.sys — simpler because HID reports are already parsed. kmdf hid minidriver for touch i2c device calibration