[ltp] getting correct time on a laptop (IBM ThinkPad T23)

[Martin Steigerwald]

Hello,

I have an IBM ThinkPad T23 with highly inaccurate clock. It misses 
accurate time by several minutes a day.

Long time I used chrony. It worked most of the time, but not always.

Right now the problems I have with chrony - see below - increased and none 
of the other approaches worked like I want.

I want the following:

1) When the laptop has internet access it should synchronise with  NTP 
time

2) Otherwise a program should correct the clock by its average inaccuracy 
(like chrony is supposed to do). That is be important cause sometimes the 
laptop is without internet access for several days.

3) Suspend to disk should be handled nicely.

4) Ideally on resume and boot the time is corrected due to NTP time or the 
inaccuracy factor via one big step.

Right now I am fighting with chrony and different other approaches and 
none of them worked like I want it to.

My problems with chrony:

1) I had chrony claiming that system time had 0 seconds difference to NTP 
time while there was a difference of 10 or more minutes. This is with a 
standard chrony installation (after aptitude purge chrony). 

2) Chrony apparantly cannot set the hardware clock. I get a input/output 
error on modprobe rtc, and it seems that the module genrtc doesn't do the 
trick. I reverted on not letting chrony do that but the usually debian 
hwclock scripts which seems to work.

3) Sometimes net access is not detected properly. I have 
copied /etc/ppp/ip-up.d/chrony and /etc/ppp/ip-down.d/chrony 
to /etc/network/if-up.d and /etc/network/if-down.d respectively in order 
to have chrony switched online and offline accordingly. I am using 
ifplugd and guessnet for automatic network configuration on demand which 
is worked quite well.

4) After suspend to disk chrony does not seem to have any NTP sources at 
all... I tried different approaches, right now I am using:

#!/bin/sh

/etc/init.d/ifplugd stop
ifdown eth0
/etc/init.d/chrony stop

# Noch nicht gespeicherte Daten sichern
sync

# Einschlafen
hibernate

/etc/init.d/chrony start
/etc/init.d/ifplugd start

Rationale for this: chrony and network are stopped before suspend since 
they do not work anyway while the notebook is powered off. After resume 
chrony is started and should be offline. Then ifplugd is started. Now 
whenever a network link is availble network is configured and chrony 
should be switched to online mode due to /etc/network/if-up.d/chrony that 
I copied there.

But apparently that doesn't work.


I also tried openntpd, which didn't even start on my system as well as the 
full blown ntp server which sort of worked, but then it does not 
provide . Once I even was desperate enough to just start ntpdate every 
hour with a cron job.


On other approach would be to fix the hardware clock such that it would be 
that much too slow. Maybe replacing the battery could help? Any other 
ideas?


Right now its extremely frustrating cause none of the approaches work to 
properly and its that I didnt try hard to make it work.

Ideally I would have something like chrony but with the enhancement that 
it would simply work even for suspend and that it just finds out itself 
whether internet access is there or not. Switching it to online and 
offline mode via scripts is just extremely error prone IMHO.

Any tricks I can play with the chrony configuration to make it work? 
chrony seems to be quite old, is upstream still alive? Any sensible 
replacement available? 


Any ideas? I greatly appreciate it when I could be able to fix up this 
time stuff without investing another dozen of hours.

If I cannot fix chrony easily I probably revert to ntp-simple for now and 
accept wrong time when the laptop is not with internet access.

Regards,
-- 
Martin 'Helios' Steigerwald - http://www.Lichtvoll.de
GPG: 03B0 0D6C 0040 0710 4AFA  B82F 991B EAAC A599 84C7