In message E1CBrKY-0004hJ-OJ@sc8-sf-mx2.sourceforge.net you wrote:

 i have some questions about u-boot 

Why are you askling the same question again?

the first : how to config stacksize in the xxx.h (this is my board's h file ) ?

I already answreed this one: you don't.

             how much is usually stack 's size?  

What do you mean? Used stack size? This depends on what you do in U-Boot (will grow if you're runnung recursive shell scripts, for example :-). Available stacksize? Depends on the size of your RAM.

              what means of "KGDB BAUDRATE"?

It's the baudrate used with KGDB.

Best regards,

Wolfgang Denk