Kmdf Hid Minidriver For Touch I2c Device Calibration Best -

Windows touch devices (I2C HID digitizers) often require calibration to map raw sensor coordinates to screen coordinates. While user-mode calibration via TouchCalibration (tabcal) exists, kernel-mode calibration inside a KMDF HID minidriver is necessary when:

This document outlines best practices for implementing calibration in a KMDF HID minidriver for an I2C touch device. kmdf hid minidriver for touch i2c device calibration best

Add calibration parameters to device context. Implement IOCTL or Feature Report set/get handlers. Windows touch devices (I2C HID digitizers) often require

Calibration must survive reboots. Options: Filtering and outlier rejection:

Recommended: Implement calibration persistence in a companion user-mode Windows service. The KMDF driver remains stateless regarding persistent storage, enhancing stability.

On EvtDevicePrepareHardware, your driver must:

// Pseudo-logic: Request HID descriptor over I2C
WDFI2C_TARGET_REQUEST_PARAMETERS_INIT(&reqParams);
// Read 4 bytes: wHIDDescLength, bcdVersion, wReportDescLength
// Extract the Report ID for calibration from the Report Descriptor later.

A HID Minidriver (also called a HID Transport Driver) sits below the class driver (HIDClass.sys). Its job is to communicate directly with the I²C controller, retrieve HID reports from the touch device, and forward them up the stack.

Touch Device (I2C) → KMDF HID Minidriver → HIDClass.sys → Touch Input Stack → User Mode