Keyboard inputs same characters?
 

Hi, Everybody.
After booting linux, if I make wifi connection, my keyboard works something strange.
On x-terminal I type about 70 characters , then same character displays automatically about 20 times.
For example,I type "abcd" continuosly like this "abcdabcdabcdabcdabcd", then it displays:

[root@localhost /]#abcdabcdabcdabcdabcdabcdabcdabbbbbbbbbbbbbbbbbbbbbbcd"

If I type again, the same problem happens again.
It happens in all editors, x terminal and editing widgets.
It also happens sometimes when I don't use wifi connection, but in this case it is difficult to remake such error.
When I boot as init 3, such problem no happens.
I switched autorepeat option of keyboard to off, with xset command and typed again.
Then output paused at the same position for some time and restarted again soon afer it.
In this case the continuous output of same character didn't happen.

[root@localhost /]#xset r off
[root@localhost /]#abcdabcdabcdabcdabcdabcdabcdabcdabcdabcdabcdabcd

What does this mean?
Does Keyboard driver send keypress event continuously to X server?
X server or its configuraion has some errors? or DBUS problem?
I really want to know the reason.
Any advice you may have would be very much appreciated...