[LinuxPPS] LinuxPPS on (k)Ubuntu

[Remco dB]

Dear all, 

Although I tried previously to run LinuxPPS on my (k)Ubuntu-machine, 
I thought that with 'real inclusion' of LinuxPPS in 2.6.34 problems would 
disappear. On my other Debian-based machines I encounter no problems
activating the PPS-API (b.t.w. on these machines the PPS-API is compiled
into the kernel and not loaded as a module). 

What I do/did:

modprobe pps_core <- no errors, in syslog:

Jun 20 23:22:19 xyz kernel: [680538.072837] LinuxPPS API ver. 1 registered
Jun 20 23:22:19 xyz kernel: [680538.072843] Software ver. 5.3.6 - Copyright 
2005-2007 Rodolfo Giometti <giometti at linux.it>

Independent of when I mknod /dev/pps0 c 253 0 (or even 254 0) or not,
ttyctrl results in the following:

remco at xyz> ttyctrl -X -s 18 /dev/ttyS0 &
[1] 6932
remco at xyz> ttyctrl: unable to set line discipline "18" for device "/dev/ttyS0" 
(Invalid argument)

[1]    Exit 1                        ttyctrl -X -s 18 /dev/ttyS0

ldattach results in: 

remco at xyz> ldattach PPS /dev/ttyS0
ldattach: cannot set line discipline: Invalid argument

or
remco at xyz> ldattach 18 /dev/ttyS0
ldattach: cannot set line discipline: Invalid argument
remco at xyz>

It doesn't matter when I sudo or not. Also access/restrictions
on /dev/ttyS0 do not matter (e.g. chmod 644, 666, 777 etc)

I saw in the Ubuntu 2.6.34 .config that the options

CONFIG_SERIAL_8250=y
CONFIG_SERIAL_8250_CONSOLE=y

In dmesg I saw that ttyS0 was selected to serve as a console.
I only have one physical RS232-port, but my system detects two.
So I added the kernel line 'console=ttyS1' in my menu.lst because 
I remembered from earlier experiences that the serial console option may 
conflict with the PPS API. 

So far no satisfying results.

Anyone here running a recent version LinuxPPS on an Ubuntu system,
and/or suggestions what to do? 

FYI, ntpd runs perfectly with a DCF77-receiver on the serial port, so the DCD-
pin of the port is accessible/readable:

remco at xyz> ntpq -p
     remote           refid      st t when poll reach   delay   offset  jitter
==============================================================================
*GENERIC(0)      .DCFa.           0 l    5   64  377    0.000    1.890   0.737
+IPv6.remco.org  .PPS.            1 u  109  512  377    0.159    0.812   0.425
+Time.remco.org  .GPS.            1 u  126  512  377    0.273    1.736   0.958
-ntp2.remco.org  .GPS.            1 u   72  512  377   39.591   -1.899   0.399


Remco