Kmdf Hid Minidriver For Touch I2c Device Calibration Best 〈Hot · CHOICE〉

Your KMDF driver should not simply forward raw touch points. It must apply a linear transformation:

[ X_calibrated = A \cdot X_raw + B \cdot Y_raw + C ] [ Y_calibrated = D \cdot X_raw + E \cdot Y_raw + F ]

Where A, B, D, E are scaling/rotation factors, and C, F are offsets. The best drivers compute these on-the-fly using a 3-point or 4-point least-squares algorithm. kmdf hid minidriver for touch i2c device calibration best

Do not attempt to modify the HID Report Descriptor dynamically to inject calibration values. The HID Report Descriptor should be static and defined in the driver's resources or code. Modifying it on the fly creates cache coherency issues with HIDClass.sys.

This document describes how to implement calibration support in a KMDF-based HID minidriver for a touch controller connected over I²C. It covers design goals, data flow, required HID usages and reports, driver components, calibration algorithms, persistent storage, and testing/validation steps. Your KMDF driver should not simply forward raw touch points

Implement a second IOCTL to delete the registry key and send a "Reset to Factory" Feature Report (usually Report ID 0x01, byte 2 = 0x01). This is critical for field maintenance.

Author: Technical Systems Engineering Subject: Windows Driver Development / HID Minidrivers Complexity: Advanced Do not attempt to modify the HID Report

typedef struct _CALIBRATION_DATA 
    LONG  XOffset;
    LONG  YOffset;
    LONG  XScale;      // Fixed-point (e.g., 1.0 = 0x10000)
    LONG  YScale;
    BOOLEAN SwapXY;
    BOOLEAN InvertX;
    BOOLEAN InvertY;
 CALIBRATION_DATA;
LONG ApplyCalibration(LONG raw, LONG offset, LONG scale, BOOLEAN invert, LONG maxVal) 
LONG calibrated = raw + offset;
calibrated = (calibrated * scale) >> 16;
if (invert) calibrated = maxVal - calibrated;
if (calibrated < 0) calibrated = 0;
if (calibrated > maxVal) calibrated = maxVal;
return calibrated;