Clock Problems

[Cas]

Hi


Noticed today that the clock on my Pandora has to be reset every so often, it just is not


keeping time.


I have to reset the time at least two to three times a day.

 

[WizardStan]

You aren't the only person to notice this. Mine and many others keep perfect time, the only time it loses time (heh) is when the battery is out, which would be expected. Not entirely certain yet why some people keep losing time.


Do you know what hotfix you're on? Hotfix 3 and earlier, putting it into low power mode would cause the clock to slow down.

 

[sporkbox]

I dunno if angstrom has this available, but look for OpenNTPD. It's a daemon that connects to an NTP (Network Time Protocol) server periodically to keep time. With some research, I'm sure you can make it correct the time only when there's a connection up.


Edit: I did something like this with my netbook, back when I had one, using netcfg (on ArchLinux). I don't know if other distros like Angstrom have netcfg.

 

[Cas]

You aren't the only person to notice this. Mine and many others keep perfect time, the only time it loses time (heh) is when the battery is out, which would be expected. Not entirely certain yet why some people keep losing time.


Do you know what hotfix you're on? Hotfix 3 and earlier, putting it into low power mode would cause the clock to slow down.

Hi


Hotfix 5.


Think you got it with the low power thing, as I do put it into the low power mode, but that's crazy, it should not work like that, should it ?

 

[MWeston]

Yeah, that makes no sense to me either. The RTC in the TPS65950 has a hardware counter. I wonder why that isn't used. It also has some trim registers to make it as accurate as possible if it was losing some seconds per day/week/month or whatever.


It must have to do with the kernel and how everything is designed to use its ticks or something but I'm no expert there.

 

[WizardStan]

Yeah, that makes no sense to me either. The RTC in the TPS65950 has a hardware counter. I wonder why that isn't used.

Constantly going back to the hardware clock is actually pretty slow in the grand scheme of computation. It's a lot faster to estimate one second and increment a software clock in memory and just refresh from the real time clock less frequently. Back at the beginning, low power mode used to drop the CPU to 14Mhz, a speed so low it couldn't keep up with the normal tasks, and the software clock suffered. With HF4, that was increased to 125Mhz and it no longer has any problems keeping up. That's why I asked which hotfix he was using. That won't be it anymore, though, mine sits in low power mode 18 hours a day and it hasn't lost any time.


Next time you notice it going way off, open a terminal and type "date & hwclock". This will show the current software and hardware clock times. If they're approximately the same (give or take a couple seconds) then there is actually a problem with the hardware clock. If they differ, then something is preventing the software clock from syncing with the hardware clock properly.

 

[myownlittlworld]

Mine tends to keep perfect time unless it's actually turned off for whatever reason. Low power mode works well, but actually shutting it off pauses the clock at the point you turned it off.

 

[WizardStan]

That shouldn't be. The hardware clock should always be ticking, and it's at least synced at startup. To have it lose time when off would mean the hardware clock is not ticking when it is off. It should always be ticking while the battery is connected. I tested this on mine 2 weeks ago: 20 minutes off and it kept perfect time.


What hotfix are you on? Has it always been like that or has something changed recently?

 

[Cas]

Hi


OK, more on the clock thing, this morning at about 9:55 I put the Pandora into low power mode.


About 20 minutes later I turned it back to full power and the clock was showing as 9:55.


I have put it back into low power mode to see if it freezes the clock at the time it is placed into


low power mode or it slows the clock down, I would think it is slowing the clock down.


it was shut down all night and when turned on this morning the time was right.


It seems what it is doing is freezing the time at when it was put into low power mode, then


when fired back up again it shows that time for long enough to make you think it is starting


again from that time, then it changes to the correct time.

 

[WizardStan]

Yes, it can take a minute for the display to update after coming out of low power mode. Same applies to the battery gauge.

 

[Neelix]

Hmm... I noticed my clock was wrong some time this week and corrected it... I don't remember exactly which day, but I think it was around Thursday.


My Pandora (which had previously been upgraded to Hotfix 5 via the PND installer) has been in and out of low power mode several times since, and is currently showing the correct time. Out of curiosity though I just ran that comparison and discovered that the hardware clock is actually out by almost 45 mins. Could it be that the current 'loss' of time issues are because it *is* periodically syncing to the hardware clock?

neelix-openpandora:~$ date           

Sun Mar 13 00:26:36 EST 2011

neelix-openpandora:~$ hwclock

Sat Mar 12 23:42:21 2011  0.000000 seconds

Come to that how do I actually update the hardware clock? it's not like the Pandora has a bios configuration utility I can trigger on startup...



EDIT: erm... never mind that last, I just figured it out... kinda obvious really LOL



EDIT 2: I'd suggest adding the following line in op_datetime.sh after the 2 date commands at the end to update the hardware clock with the newly set timezone and time.

hwclock -wl

As a matter of interest, why is the screensaver turned off beforehand then turned back on?


EDIT 3: removed tautology in edit 2.

 

[Neelix]

hmmm... I accidentally let my battery go flat last night. Once I got the pandora charged again I discovered that the clocks had both lost ~5 mins. (but were still synced)