Help: gdb xfree86 video card driver on rh9

[harry]

I am debuging a video card driver on XFree86.I was using gdb 5.1.1-2.0xfree on radhat 9.0. And I had tried : (1) I was using "gdb /usr/X11R6/bin/XFree86" , then run. It result as "Segmentation fault". (2) During build sis_drv.o, I had using para "-g" for gcc.    "startx" open Xwindow fristly, then using  "ps ax" gets the processid of "X :0".      use SSH login    and  "gdb /usr/X11R6/lib/modules/drivers/sis_drv.o processid". By this way, i could see source codes and function symbols of the sis_drv.o , and could set breakpoints. But Xwindow will not break at those points that i setted.What's wrong on my ways to debug video driver of xfree86 bu gdb?       Now i only could use print message to debug,but that is troublesome. If anybody has some suggestion as how to debug  I would gladly appreciate any suggestions. Thanks   Harry Cheng [EMAIL PROTECTED]