Date: Thu, 19 Aug 2010 21:38:33 +1000 From: Peter Jeremy <peterjeremy@acm.org> To: phil hefferan <wdef200@gmail.com> Cc: freebsd-hackers@freebsd.org Subject: Re: Reading rtc on FreeBSD Message-ID: <20100819113833.GA59397@server.vk2pj.dyndns.org> In-Reply-To: <AANLkTinu-7wxfHU3OweQ3rM9P6DvR10gTxNYys8OEpjq@mail.gmail.com> References: <AANLkTinu-7wxfHU3OweQ3rM9P6DvR10gTxNYys8OEpjq@mail.gmail.com>
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--cNdxnHkX5QqsyA0e Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Repeating your question will not encourage an answer. On 2010-Aug-19 13:09:46 +0300, phil hefferan <wdef200@gmail.com> wrote: >I've been looking around for how to read the cmos/rtc on FreeBSD. There is >no hwclock utility in FreeBSD that I can read sources for to see how it is >done. The RTC is only accessed within the kernel (/sys/isa/atrtc.c for i386 and amd64) and read in /sys/kern/subr_rtc.c::inittodr() >implies that, on FreeBSD, gettimeofday reads the software time and >settimeofday sets the cmos clock. I read here >http://www.mail-archive.com/freebsd-hardware@freebsd.org/msg03414.html that >settimeofday in fact sets both rtc and system time together. gettimeofday(2) reads the software clock only. settimeofday(2) writes both the software clock and RTC. >BUT the source to adjkerntz.c for FreeBSD seems to say that gettimeofday >reads the CMOS clock not the system time: > >/* get local CMOS clock and possible kernel offset */ >if (gettimeofday(&tv, &tz)) { > syslog(LOG_ERR, "gettimeofday: %m"); > return 1; >} That comment is incorrect. >Which is it? Does gettimeofday read the cmos clock/rtc on FreeBSD? If not, >how do I read the battery-backed clock on FreeBSD? There is no managed access to the RTC in FreeBSD. Your only option to read the RTC is to directly access its IO port registers via io(4) or i386_set_ioperm(2) --=20 Peter Jeremy --cNdxnHkX5QqsyA0e Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.15 (FreeBSD) iEYEARECAAYFAkxtF7kACgkQ/opHv/APuId4UwCeIX0Oqg38buhFxD/QoQvEq5D5 DI0An1ZUAuMvI2SglELi62p9jO4858Gl =Vkpr -----END PGP SIGNATURE----- --cNdxnHkX5QqsyA0e--
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