Re: [chrony-users] RTC Trimming Issues

[Ed W <lists@xxxxxxxxxxxxxx>]

On 30/10/2012 13:54, John.Florian@xxxxxxxx wrote:

> - Can you set the correct (ish) time with hwclock?

This looks broken too:

# date
Tue Oct 30 09:28:01 EDT 2012
# hwclock --systohc
hwclock: select() to /dev/rtc to wait for clock tick timed out: Success
# hwclock --show
hwclock: select() to /dev/rtc to wait for clock tick timed out: Success

> When you reboot does it stay set?

Given the above results, I suspect this is irrelevant, but just for grins, I rebooted it and found a "surprise inside":

Hi, I see *exactly* your problems with my PCEngines Alix 2D3 boards.  About 30% of boards seem to boot and the RTC driver seems borked, therefore you can't set the clock with chrony, but a *warm* reboot and the RTC starts correctly next time and hence you can set it, and after that it all seems to work...

I haven't really debugged this, but:
- Boards have cmos batteries
- bolloxed boards show a time which looks feasibly like 2000 + some number of days since battery inserted, ie RTC is kind of working
- lots of clock based problems on boot, rtc not working, seems to cascade in strange ways and then networking won't start and lots of cascading issues. Not debugged the chain of events though. I think only a warm reboot gets RTC working, and then it can be set

- *Feels* like some RTC are in some invalid state on boot and the kernel driver pukes
- Warm reboot allows the kernel rtc driver to start
- Setting "something" in the RTC then makes it work correctly there onwards...


Therefore suspect some RTC clocks can be in an "initial" state which the kernel driver doesn't correctly handle and initialise. Probably worth filing some bug with kernel guys, perhaps even posting someone a board, but I'm at capacity right now to debug this... Doesn't seem like a chrony issue anyway

I think if you can bear to do a one off script when you get new machines to ensure a warm reboot and RTC reset, then they will all behave fine thereafter?  If you find this then please document here for benefit of all? 

Good luck

Ed W