System Hang on inputing switching between modbus & rmsmod...[Corrected]

1. modbus OFF
2. input SYSCFG ( don't exit)
3. modbus ON
4. modbus OFF
5. input some ...
all the input chars are echoed, but when entering "ENTER" key.
system hang ! AXD shows : hang on queue copy : case sizeof(char).

Not knowing why . now.

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Found !! - on switching Com1drv mode (Rms/Modbus).
do Purgequeue (IQ,OQ), so ..
after comment out these 2 lines, this symdrom is out.


2.3pr3 , CxU software, modbus, com, 232, at91, bug