Date: Fri, 20 Aug 2010 10:55:35 +0300 From: phil hefferan <wdef200@gmail.com> To: bf1783@gmail.com Cc: freebsd-hackers@freebsd.org Subject: Re: How to read cmos clock - what is gettimeofday reading? Message-ID: <AANLkTinpyOe%2BkLPGYqobfKA_xTR8PNk50t55O9gVwUiE@mail.gmail.com> In-Reply-To: <AANLkTimNLAdPYQ0-yqyvR4YEuUsEG%2Bmc7rFQ%2BWZUAvYh@mail.gmail.com> References: <AANLkTimNLAdPYQ0-yqyvR4YEuUsEG%2Bmc7rFQ%2BWZUAvYh@mail.gmail.com>
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On Fri, Aug 20, 2010 at 5:17 AM, b. f. <bf1783@googlemail.com> wrote: > >To further confuse matters there appears to be a common misconception on > the web > >that the cmos time is automatically synced to system time on FreeBSD. This > is > >incorrect: see msg03414 on freebsd-hardware at freebsd.org. > > The situation has changed in 8-STABLE and 9-CURRENT since the above > message was written. The timekeeping code was changed (by the person > who wrote the message that you cited) to periodically (every > machdep.rtc_save_period seconds) adjust the value of the rtc if ntp is > used to update the system time, machdep.disable_rtc_set=0, and the rtc > driver hasn't been disabled: > > http://svnweb.freebsd.org/viewvc/base?view=revision&revision=207360 > http://svnweb.freebsd.org/viewvc/base?view=revision&revision=208297 > > atrtc_{get,set}time, now in /usr/src/sys/x86/isa/atrtc.c, could serve > as a basis for your own code: > > http://svn.freebsd.org/viewvc/base/head/sys/x86/isa/atrtc.c?view=markup > > There are of course *_rtc_{get,set}time variants for other > architectures as well. > > Thanks for that. I'll look at atrtc_gettime.
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