Brightness Driver For: Windows 11

switch (IoControlCode) case IOCTL_SET_BRIGHTNESS: // 1. Extract user-mode request WdfRequestRetrieveInputMemory(Request, &memory); req = (BRIGHTNESS_REQUEST*)WdfMemoryGetBuffer(memory, NULL); // 2. Convert 0-100 to hardware PWM value (e.g., 0-255) UCHAR pwmValue = (req->Level * 255) / 100; // 3. Write to hardware (example: ACPI EC port) WRITE_PORT_UCHAR((PUCHAR)0xB2, pwmValue); // 4. Complete request WdfRequestComplete(Request, STATUS_SUCCESS); break; default: WdfRequestComplete(Request, STATUS_INVALID_DEVICE_REQUEST);

VOID DeviceIoControl( WDFQUEUE Queue, WDFREQUEST Request, size_t OutputBufferLength, size_t InputBufferLength, ULONG IoControlCode ) BRIGHTNESS_REQUEST* req; WDFMEMORY memory; brightness driver for windows 11

But what happens when that breaks? What happens when you build a custom portable monitor, run a Hackintosh, or use a Linux VM with GPU passthrough? Suddenly, the brightness slider in Windows 11 disappears, and the Fn keys do nothing. switch (IoControlCode) case IOCTL_SET_BRIGHTNESS: // 1