please anyone here help me to solve this problem.

I am working on linux 2.4.19 (arm based) + qt-embedded-free-3.3.8b.
and now I am writing a custom keyboard handler which subclass from QWSKeyBoardHandler.

Qt Code: 
  1. class MyKbdHandler: public QObject, public QWSKeyBoardHandler {
  2.     Q_OBJECT
  3. public:
  4.     MyKbdHandler();
  5.     ~MyKbdHandler();
  6.  
  7. private slots:
  8.     void readKbdData();
  9.  
  10. private:
  11.     QSocketNotifier *m_kbdNotifier;
  12.     int m_kbdFd;
  13. }
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Qt Code: 
  1. MyKbdHandler::MyKbdHandler()
  2. : QObject(), QWSKeyBoardHandler()
  3. {
  4.     m_kbdNotifier = NULL;
  5.     m_kbdFd = ::open("/dev/input", O_RDONLY|O_NONBLOCK);
  6.     if (m_kbdFd < 0) {
  7.         qDebug("Can not open input device!\n");
  8.         return;
  9.     }
  10.  
  11.     m_kbdNotifier = new QSocketNotifier(m_kbdFd, QSocketNotifier::Read, this);
  12.     connect(m_kbdNotifier, SIGNAL(activated(int)), this, SLOT(readKbdData()));
  13. }
  14.  
  15. MyKbdHandler::~MyKbdHandler()
  16. {
  17.     if (m_kbdFd >= 0) {
  18.         ::close(m_kbdFd);
  19.         m_kbdFd = -1;
  20.     }
  21.  
  22.     if (m_kbdNotifier != NULL) {
  23.         delete m_kbdNotifier;
  24.         m_kbdNotifier = NULL;
  25.     }
  26. }
  27.  
  28. MyKbdHandler::readKbdData()
  29. {
  30.  
  31.     char buf[1024] = { 0 };
  32.     int n = ::read(m_kbdFd, buf, sizeof(buf));
  33.     qDebug("MyKbdHandler::readKbdData = %d\n", n);
  34.  
  35.     // do key code mapping and call processKeyEvent here ...
  36.  
  37. }
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after reading all of the available data(the read call already return 0), the activated() signal emit over and over again, and readKbdData() also get invoked. the cpu reached to 98%.!

any idea ?