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Diffstat (limited to 'share/man/man4/atrtc.4')
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diff --git a/share/man/man4/atrtc.4 b/share/man/man4/atrtc.4 new file mode 100644 index 0000000..0b0dd8f --- /dev/null +++ b/share/man/man4/atrtc.4 @@ -0,0 +1,57 @@ +.\" Copyright (c) 2010 Alexander Motin <mav@FreeBSD.org> +.\" All rights reserved. +.\" +.\" Redistribution and use in source and binary forms, with or without +.\" modification, are permitted provided that the following conditions +.\" are met: +.\" 1. Redistributions of source code must retain the above copyright +.\" notice, this list of conditions and the following disclaimer. +.\" 2. Redistributions in binary form must reproduce the above copyright +.\" notice, this list of conditions and the following disclaimer in the +.\" documentation and/or other materials provided with the distribution. +.\" +.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND +.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE +.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE +.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE +.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL +.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS +.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) +.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT +.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY +.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF +.\" SUCH DAMAGE. +.\" +.\" $FreeBSD$ +.\" +.Dd September 17, 2010 +.Dt ATRTC 4 +.Os +.Sh NAME +.Nm atrtc +.Nd AT Real-Time Clock (RTC) driver +.Sh SYNOPSIS +This driver is a mandatory part of i386/amd64 kernels. +.Pp +The following tunable is settable from the +.Xr loader 8 : +.Bl -ohang +.It Va hint.atrtc. Ns Ar X Ns Va .clock +controls event timers functionality support. Setting to 0, disables it. +Default value is 1. +.El +.Sh DESCRIPTION +This driver uses RTC hardware to supply kernel with time-of-day clock +with 1 second resolution and one event timer. +This hardware uses base frequency of 32768Hz for advancing time-of-day clock +and generating periodic interrupts. +Interrupts could be generated with fixed number of frequencies, from 2Hz to +8192Hz, obtained by dividing base frequency by one of supported power-of-2 +divisors. +.Pp +Event timer provided by the driver is irrelevant to CPU power states. +.Sh SEE ALSO +.Xr apic 4 , +.Xr attimer 4 , +.Xr eventtimers 4 , +.Xr hpet 4 |