Kmdf Hid Minidriver For Touch I2c Device Calibration -

Ycal=D⋅Xraw+E⋅Yraw+Fcap Y sub c a l end-sub equals cap D center dot cap X sub r a w end-sub plus cap E center dot cap Y sub r a w end-sub plus cap F

Raw coordinate data from a touchscreen often doesn't align perfectly with the display behind it. Issues can include:

Your KMDF driver must retrieve these factors (A, B, C, D, E, F) during initialization and apply them to every incoming HID input report before passing the packet up to HIDClass . 3. Retrieving Calibration Data via ACPI (_DSM) kmdf hid minidriver for touch i2c device calibration

DriverEntry -> WdfDriverCreate -> EvtDeviceAdd

NTSTATUS RetrieveCalibrationFromACPI( _In_ WDFDEVICE Device, _Out_ PVOID CalibrationBuffer, _In_ ULONG BufferSize ) NTSTATUS status; ACPI_EVAL_INPUT_BUFFER_COMPLEX inputBuffer = 0 ; PACPI_EVAL_OUTPUT_BUFFER outputBuffer = NULL; ULONG outputLength = 0; // 1. Initialize ACPI input arguments with the Touch _DSM UUID inputBuffer.Signature = ACPI_EVAL_INPUT_BUFFER_COMPLEX_SIGNATURE; inputBuffer.MethodNameAsUlong = (ULONG)'MSD_'; // _DSM reversed inputBuffer.ArgumentCount = 4; // (Fill out UUID, Revision, Function Index, and Empty Package arguments here...) // 2. Send the IOCTL_ACPI_EVAL_METHOD to the underlying bus status = WdfIoTargetSendIoctlSynchronously( WdfDeviceGetIoTarget(Device), NULL, IOCTL_ACPI_EVAL_METHOD, &inputMemoryDescriptor, &outputMemoryDescriptor, NULL, NULL ); if (NT_STATUS_IS_SUCCESS(status)) // Parse outputBuffer down to coefficients and copy to CalibrationBuffer return status; Use code with caution. 4. Injecting Calibration into the HID Parsing Pipeline Ycal=D⋅Xraw+E⋅Yraw+Fcap Y sub c a l end-sub equals

// Define the HidGetCalibrationData routine NTSTATUS HidGetCalibrationData( _In_ WDFDEVICE Device, _Out_ PCALIBRATION_DATA CalibrationData )

If you want to explore the user-mode side of this setup, I can provide a that calculates these matrices from user screen taps. _Out_ PVOID CalibrationBuffer

During the driver's EvtDevicePrepareHardware phase, you can evaluate the ACPI object to extract calibration parameters directly from UEFI/BIOS. Conceptual ASL (ACPI Source Language) Patch

[HID_Inst.NT] Include = machine.inf Needs = HID_Inst.NT AddReg = HID_AddReg

Calibration typically falls into two categories: and Runtime/Dynamic Calibration .