Date: Tue, 3 Jun 2014 19:25:39 +0000 (UTC) From: Christian Brueffer <brueffer@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-10@freebsd.org Subject: svn commit: r267022 - stable/10/share/man/man4 Message-ID: <201406031925.s53JPdOg037650@svn.freebsd.org>
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Author: brueffer Date: Tue Jun 3 19:25:39 2014 New Revision: 267022 URL: http://svnweb.freebsd.org/changeset/base/267022 Log: MFC: r266709 Language cleanup. Reviewed by: mav, bcr, wblock Modified: stable/10/share/man/man4/attimer.4 Directory Properties: stable/10/ (props changed) Modified: stable/10/share/man/man4/attimer.4 ============================================================================== --- stable/10/share/man/man4/attimer.4 Tue Jun 3 19:24:53 2014 (r267021) +++ stable/10/share/man/man4/attimer.4 Tue Jun 3 19:25:39 2014 (r267022) @@ -24,7 +24,7 @@ .\" .\" $FreeBSD$ .\" -.Dd September 14, 2010 +.Dd May 26, 2014 .Dt ATTIMER 4 .Os .Sh NAME @@ -37,38 +37,48 @@ The following tunables are settable from .Xr loader 8 : .Bl -ohang .It Va hint.attimer. Ns Ar X Ns Va .clock -controls event timers functionality support. Setting to 0, disables it. -Default value is 1. +controls support for the event timer functionality. +Setting this value to +.Dv 0 +disables it. +The default value is +.Dv 1 . .It Va hint.attimer. Ns Ar X Ns Va .timecounter -controls time counter functionality support. Setting to 0, disables it. -Default value is 1. +controls support for the time counter functionality. +Setting this value to +.Dv 0 +disables it. +The default value is +.Dv 1 . .It Va hw.i8254.freq -allows to override default counter frequency. -The same value is also available in run-time via +allows overriding the default counter frequency. +The same value is also available at run-time via the .Va machdep.i8254_freq sysctl. .El .Sh DESCRIPTION This driver uses i8254 Programmable Interval Timer (AT Timer) hardware -to supply kernel with one time counter and one event timer, and generate -sound tones for system speaker. +to supply the kernel with one timecounter and one event timer, and to generate +sound tones for the system speaker. This hardware includes three channels. -Each channel includes 16bit counter, counting down with known, +Each channel includes a 16 bit counter which decreases with a known, platform-dependent frequency. Counters can operate in several different modes, including periodic and one-shot. -Output of each channel has platform-defined wiring: one channel is wired +The output of each channel has platform-defined wiring: one channel is wired to the interrupt controller and may be used as event timer, one channel is -wired to speaker and used to generate sound tones, and one timer is reserved +wired to the speaker and used to generate sound tones, and one timer is reserved for platform purposes. .Pp -Driver uses single hardware channel to provide both time counter and event +The +.Nm +driver uses a single hardware channel to provide both time counter and event timer functionality. -To make it possible, respective counter must be running in periodic more. -As result, one-shot event timer mode supported only when time counter +To make this possible, the respective counter must be running in periodic mode. +As a result, the one-shot event timer mode is supported only when time counter functionality is disabled. .Pp -Event timer provided by the driver is irrelevant to CPU power states. +The event timer provided by the driver is irrelevant to CPU power states. .Sh SEE ALSO .Xr apic 4 , .Xr atrtc 4 ,
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