IGameInputDevice::GetRawDeviceFeature

HRESULT GetRawDeviceFeature(
    uint32_t reportId,
    IGameInputRawDeviceReport** report
);

Microsoft::WRL::ComPtr<IGameInputRawDeviceReport> report;
if (SUCCEEDED(device->GetRawDeviceFeature(reportId, &report)))
{
    std::vector<uint8_t> data(report->GetRawDataSize());
    data.resize(report->GetRawData(data.size(), data.data()));
    // Parse the device-specific feature report data...
}