Mouse problem under RedHat's framebuffer

I use SDL 1.2.6 under Redhat’s framebuffer. Everything is ok, but

the mouse is on the left-top corner of the screen. It cannot move. I have

start gpm, and export SDL_MOUSEDEV_IMPS2=1.

  If I start gpm with "-R imps2 -m /dev/psaux", the mouse can move but

jump to left or top quickly. And in SDL_MOUSEMOTION event case, I see

event.motion.x<0, or event.motion.y<0.

  What's the matter? How can I do?

I export “SDL_MOUSEDEV=/dev/psaux” or “SDL_MOUSEDEV=/dev/psmouse” or
"SDL_MOUSEDEV=/dev/mouse", and I stop gpm or start gpm by
"/etc/init.d/gpm start" (the option is “-t imps2 -m /dev/psaux”), I get
the same result as above.