[LinuxPPS] some problems with linuxPPS + GPS system

[david]

Dear all,

I try to install on a pc with VIA processor a ntp system with a GP18LVC
garmin GPS.

I use debian and recompile the kernel with 2.6.26 kernel and the diff
file ntp-pps-2.6.26.diff

I follow the wiki but I had problem to get pps information.

I found this difference with the wiki :

1) I need to load ktimer to have an answer at the command : tree
/sys/class/pps

2) the result show device missing field

/sys/class/pps
|-- pps0
|   |-- assert
|   |-- clear
|   |-- dev
|   |-- echo
|   |-- mode
|   |-- name
|   |-- path
|   |-- power
|   |   `-- wakeup
|   |-- subsystem -> ../../pps
|   `-- uevent
`-- pps1
     |-- assert
     |-- clear
     |-- dev
     |-- echo
     |-- mode
     |-- name
     |-- path
     |-- power
     |   `-- wakeup
     |-- subsystem -> ../../pps
     `-- uevent

6 directories, 18 files

3) ./ppsfind /dev/ttyS0 give :

pps0: name=serial0 path=/dev/ttyS0

In the wiki this is pps1 (is it important ?)

4) I patch ntpd with the file nmea.patch and when I try to get ntpq -p
information, I always had NMEA and not PPS like this :

/usr/src/ntp-4.2.2p4/ntpq/ntpq -pn
      remote           refid      st t when poll reach   delay   offset
  jitter
==============================================================================
*127.127.20.0    .GPS.            0 l   18   16  377    0.000   10.107
  3.417

5) my ntp.conf is :

# /etc/ntp.conf, configuration for ntpd

driftfile /var/lib/ntp/ntp.drift
statsdir /var/log/ntpstats/
logfile /var/log/ntpd.log

statistics loopstats peerstats clockstats
filegen loopstats file loopstats type day enable
filegen peerstats file peerstats type day enable
filegen clockstats file clockstats type day enable

logconfig = +syncall +clockall +sysall +peerall
statistics loopstats peerstats clockstats

# LinuxPPS: GPS + PPS
server 127.127.20.0 prefer minpoll 4
fudge 127.127.20.0 flag3 1 flag2 0 time1 0.0

# By default, exchange time with everybody, but don't allow configuration.
# See /usr/share/doc/ntp-doc/html/accopt.html for details.
restrict -4 default kod notrap nomodify nopeer noquery
restrict -6 default kod notrap nomodify nopeer noquery

# Local users may interrogate the ntp server more closely.
restrict 127.0.0.1
#restrict ::1


I don't understand why I don't had the PPS information in ntpd

I try to long PPS pulse to 200ms (I read something about problems on
web) without success.

Thanks in advance for helping.

David
Network Team
Cisteme / Limoges / France