[Touch_Device.NT.HW] AddReg = Touch_Device_AddReg [Touch_Device_AddReg] HKR,,"CalibrationOffsetX",0x00010001, 12 ; DWORD offset adjustment X HKR,,"CalibrationOffsetY",0x00010001, -8 ; DWORD offset adjustment Y HKR,,"TouchFilteringGain",0x00010001, 100 ; Scale modifier for tracking raw delta values Use code with caution. Loading Parameters in KMDF
switch (eventType) case CALIBRATION_EVENT_USER_INPUT: // Handle user input during calibration break; case CALIBRATION_EVENT_DEVICE_NOTIFICATION: // Handle device notifications during calibration break;
0x06, 0x00, 0xFF, // USAGE_PAGE (Vendor Defined) 0x09, 0x01, // USAGE (Calibration Control) 0xA1, 0x01, // COLLECTION (Application) 0x85, 0x02, // REPORT_ID (2) 0x09, 0x02, // USAGE (Trigger Calibration Command) 0x15, 0x00, // LOGICAL_MINIMUM (0) 0x25, 0x01, // LOGICAL_MAXIMUM (1) 0x75, 0x08, // REPORT_SIZE (8) 0x95, 0x01, // REPORT_COUNT (1) 0xB1, 0x02, // FEATURE (Data,Var,Abs) 0xC0 // END_COLLECTION Use code with caution. Processing IOCTL_HID_SET_FEATURE kmdf hid minidriver for touch i2c device calibration best
For many touchscreens (single-touch or MT), this simplifies to scaling and offset:
A touch controller (e.g., Goodix, Elan, Cypress) exposes registers: [Touch_Device
Your KMDF driver should not simply forward raw touch points. It must apply a linear transformation:
Run !wdfkd.wdfverifier in WinDbg. The best drivers pass all KMDF rule checks (e.g., WdfDeviceInitApi , RequestReuse ). Calibration IOCTLs must never leak WDFREQUEST objects. It must apply a linear transformation: Run
Since I2C touch devices often lose calibration on power loss, your KMDF driver must use the system registry for persistence.
A HID minidriver works under the umbrella. It handles transport-specific details (I2C read/write) while HIDClass parses reports. Your driver does not need to re-implement HID parsing—only the transport and calibration logic.
Apply lookup arrays matching coordinate segments to normalize pixel mapping. AC charger noise or ripple voltages