[SOLVED] Time is changed after every reboot

Question

Hello,
my Arch has strange behaviour regarding the system time. I use latest up-to-date arch with KDE. No explicite NTPD running and I don't have it in DAEMONS under rc.conf. The KDE own time & date environment is configured to not automatically change time. In /etc/rc.conf I have HARDWARECLOCK="localtime" and TIMEZONE="America/Chicago". Now from the environment to the problem:
Whenever I shutdown or restart my system, the time will be changed after booting into linux again. After shutdown with correct time using "date -s ..", the BIOS clock is correct. Then, when it actually boots into arch, there will be a delay
of 20-40 seconds for "$ date" (approximatelly the time of the reboot process) and also in the BIOS clock!
After shuting down before going to bed and restarting in the morning, the time will be approximately (or more or less exactly) the time when I shutted down... It should not be related to KDE as I observe the same behaviour when I remove kdm from daemons in rc.conf, hence, booting to console, setting time, restarting into console...
As I have dual boot: this problem is not observable using windows...
It seems like the time is stored somewhere during shutdown process and changed accordingly during reboot...?!?
Any ideas or comments? It's really crazy how annoying a wrong computer clock becomes (all IMs and system stuff is based on it...). :-(
Last edited by ichbinder (2010-10-10 09:11:01)

Answer 1

Thanks for all the quick responses!
Primoz wrote:maybe you should start using ntp or openntpd?
It provides you with time directly from the net.
Well, I tried to use ntp. As I am using KDE, there should already be a synchronisation service active. I can activate synchronisation in System Settings -> Date & Time and it works right after activation. But further on, e.g. after a restart - and hence such a wrong time as described in my first post - it does not correct anything. So it seems like, there is also a problem with this KDE synchronisation. But to state why I'm not using it anymore: it doesn't make much sense to use it as this is just a work around and does not solve the problem that the hardware clock might become wrong (so, e.g. I end up with a wrong clock in windows or so). In general, I just want to have a correct clock without synchronisation before I activate synchronisation.
ewaller wrote:
That seems weird.
When you power up, what happens if, before starting your boot loader, you enter the BIOS set up and check the system time?
Yes, it is. Well, if the hardware clock has been set correctly using e.g. hwclock it will be correct in BIOS before I restart arch. Similar observations for the following case:
- set HW clock correct in BIOS
- start arch ... shutdown arch
- check HW clock in BIOS -> correct
- start arch ... shutdown arch
- check HW clcok in BIOS -> incorrect
ewaller wrote:...
Other thoughts:  date -s does not set the BIOS clock, it sets the Linux kernel time.  On what do you assert that the BIOS clock is correct at shutdown.
Thanks for the hint! In that case, it seems like the KDE Date & Time settings influence both, hwclock and date.
ewaller wrote:...
Also, once booted into Linux, what does the command hwclock show?  This command reads the actual BIOS hardware clock.
Yeah, I used that alot now. So as described, it is also incorrect after a restart. But only after arch has booted again. To sum it up:
Using whatever tools to set the hardware clock and the system clock (KDE's tool, hwclock + date, or BIOS + date), both are correct until I reboot into arch the next time. If I do that, it resets both to a time similar to the last shutdown time.
karol wrote:
This doesn't fix anything, but you can try https://bugs.archlinux.org/task/13684#comment52246 - using UTC instead of localtime.
I never checked if my system clock is running perfect at all times or is /etc/cron.hourly/adjtime correcting it once in a while.
Hm, not to sure what they are doing exactly there and how this might help... :-/
What do you mean with the second part of the sentence? Not sure if /etc/chron.hourly/adjtime is doing anything in my case... How can I check if that cronjob is running?
karol wrote:Have you tried this http://wiki.archlinux.org/index.php/Time#Time_Skew ?
But this is very interesting! I will remove /var/lib/hwclock/adjtime  as described in the wiki and see what happens then. Thanks!