[LinuxPPS] parallel port pps info

[gnu not unix]

Hi Folks--

I have pps out of a Spectracom Netclock/2, a radio clock that
uses the LF signal at 60 KHz with a time code (known here as WWVB).
So I set up the ttl level pps output of this clock as a feed for the
parallel port input to the linuxpps host. The syslog shows this entry
when I used the lp driver:

Jul  6 11:37:38 nimbus kernel: 
     lp0: using parport0 (interrupt-driven).

Jul  6 11:37:38 nimbus kernel: 
     new PPS source parport0 at ID 1

Jul  6 11:37:38 nimbus kernel: 
     parport_pc parport_pc.888: PPS source #1 "/dev/lp0" added

And the /dev/pps1 entry also shows up. This fed a pps signal ok,
except that it seemed to override the GPS pps signal, so I unloaded
the lp module and replaced it with the ppsdev module so I could
run the userspace shm pps program.

The shm program worked fine, however it seemed to perturb the linuxpps
badly. The offset shown in the shm program became the offset shown
by ntpd. This is very confusing, I had not configured a shm driver
in ntpd, and I had unloaded the lp module, so I can't even imagine
how the ntpd could be affected. Even after I stopped the shm
program the offset seemed to still be tweaked by the parallel port
input. Only after i *physically disconneced* the cable does the
GPS pps signal take over again

It feels like I've really Lost It (cough, american slang for 
flipping out, losing your marbles, few cards short of a full deck,
etc etc).

Has anyone else tried multiple linuxpps pps inputs? 

//Steve
making Extra Strong coffee now