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Re: TS-7200: time sync issues

Ken Hornstein wrote:
A P.S.  Looks like I'm wrong.  Looks like it uses tsrtc, which is a
mc146818 device, which has a dangerous looking mc146818_settime_ymdhms
also done at splclock() (which I think may be unneeded these days).
If the part takes a long time to reply...

Ouch, I missed the splclock() in mc146818.c.  Yeah, I don't know how
slow writes are to that bus, but that could be a likely culprit.  And
I even see that the splclock() call is marked "XXX really needed?".  And
as I trace back up the call path, I see that resettodr() is right after
the splx() call in kern_time.c, which tells me that the idea was that
the todr is NOT supposed to be set at splclock().  And now that I think
about it, I cannot come up with any reason why clock interrupts should be
blocked during the setting of the time-of-day clock; can anyone else?

Those bus cycles should be approximately 320 nS each. The RTC has no connection to the processor WAIT# signal so its not possible for it to extend bus cycles. That UIP bit will be set some ?? uS before a once per second update. As long as you have a functioning battery-backed RTC (TS-5620) on the PC104 bus, that UIP should only be set for a very short time that should be of no consequence.
//Jesse Off

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