Josephyu 
Hi I set kgdboc=s3c2410_serial3,460800 kgdbwait in kernel cmdline. I try to send break in sysrq. But there is no 'g' for sysrq... I used the minicom to send break, no result in gdb... "hell@android:/ # echo g > /proc/sysrq-trigger [ 635.530000] SysRq : HELP : loglevel(0-9) reBoot Crash terminate-all-tasks(E) memory-full-oom-kill(F) kill-all-tasks(I) thaw-filesystems(J) show-backtrace-all-active-cpus(L) show-memory-usage(M) nice-all-RT-tasks(N) powerOff show-registers(P) show-all-timers(Q) Sync show-task-states(T) Unmount show-blocked-tasks(W) dump-ftrace-buffer(Z)" BR