XFree86 4.1/4.2, QNX and Elo touch

I am trying to get XFree86 4.1 or 4.2 up and running with a serial ELO touch
screen under QNX 6.1, using the ELO touch screen module under XFree86.

I works to some degree but XFree86 event processing hangs until I move the
cursor through the touch screen. For instance - if I type some thing in a
terminal window it will not show up until I move the cursor around with the
touch screen. It is almost like XFree86 is blocked by the touch screen.

I tried to set the serial device to raw (stty +raw < /dev/ser1) but that
didn't make any difference.

Any ideas?

Thanks
Jens