24013109f5
device and module naming. The following files were repo-copied: csa.4 -> snd_csa.4 gusc.4 -> snd_gusc.4 maestro3.4 -> snd_maestro3.4 sbc.4 -> snd_sbc.4 uaudio.4 -> snd_uaudio.4 The pcm(4) manpage wasn't renamed to sound(4) as there are nearby plans to rename "device sound" to "device snd", to address the ambiguity in naming, so pcm.4 is linked to sound.4 for the moment. (We also mumble something about the future plans in the manpage.) Removed links from pcm.4 to als4000.4 and emu10k1.4 -- they now have their own snd_*.4 manpages. Fixes for recent snd_*.4 manpages: added missing "device sound" to the SYNOPSIS, fixed hints (they are still "hint.pcm.<unit>" in most cases). MT5 after: 3 days
389 lines
10 KiB
Groff
389 lines
10 KiB
Groff
.\"
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.\" Copyright (c) 1998, Luigi Rizzo
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.\" All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" $FreeBSD$
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.\"
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.Dd August 28, 2004
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.Dt SOUND 4
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.Os
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.Sh NAME
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.Nm sound ,
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.Nm pcm ,
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.Nm snd
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.Nd
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.Fx
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PCM audio device infrastructure
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.Sh SYNOPSIS
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For a card with bridge driver support, and a PnP card:
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.Cd "device sound"
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.Pp
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For a card without bridge driver support, and a non-PnP card,
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the following lines may be required in
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.Pa /boot/device.hints :
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.Cd hint.pcm.0.at="isa"
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.Cd hint.pcm.0.irq="5"
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.Cd hint.pcm.0.drq="1"
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.Cd hint.pcm.0.flags="0x0"
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.Sh DESCRIPTION
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.Bf -emphasis
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Note: There exists some ambiguity in the naming at the moment
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.Pq Nm sound , pcm , snd .
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It will be resolved soon by renaming
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.Cd "device sound"
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to
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.Cd "device snd" ,
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and doing associated changes.
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.Ef
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.Pp
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The
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.Nm
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driver provides support for
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.Tn PCM
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audio play and capture.
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This driver also supports various
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.Tn PCI ,
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.Tn WSS/MSS
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compatible,
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.Tn ISA
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sound cards, and AC97 mixer.
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Once the
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.Nm
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driver attaches, supported devices provide audio record and
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playback channels.
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The
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.Fx
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sound system provides dynamic mixing
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.Dq VCHAN
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and rate conversion
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.Dq soft formats .
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True full duplex operation is available on most cards.
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.Pp
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If the sound card is supported by a bridge driver, the
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.Nm
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driver works in conjunction with the bridge driver.
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.Pp
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Apart from the usual parameters, the flags field is used to specify
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the secondary
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.Tn DMA
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channel (generally used for capture in full duplex cards).
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Flags are set to 0 for cards not using a secondary
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.Tn DMA
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channel, or to 0x10 + C to specify channel C.
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.Pp
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The driver works best with
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.Tn WSS/MSS
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cards, which have a very clean
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architecture and an orthogonal set of features.
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They also happen to be
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among the cheapest audio cards on the market.
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.Pp
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The driver does its best to recognize the installed hardware and drive
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it correctly so the user is not required to add several lines in
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.Pa /boot/device.hints .
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For
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.Tn PCI
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and
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.Tn ISA
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.Tn PnP
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cards this is actually easy
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since they identify themselves.
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For legacy
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.Tn ISA
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cards, the driver looks for
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.Tn MSS
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cards at addresses 0x530 and 0x604 (unless overridden
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in
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.Pa /boot/device.hints ) .
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.Ss Boot Variables
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In general, the module
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.Pa snd_foo
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corresponds to
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.Cd "device snd_foo"
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and can be
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loaded by the boot
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.Xr loader 8
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via
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.Xr loader.conf 5
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or from the command line using the
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.Xr kldload 8
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utility.
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Options which can be specified in
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.Pa /boot/loader.conf
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include:
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.Bl -tag -width ".Va snd_emu10k1_load" -offset indent
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.It Va snd_driver_load
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.Pq Dq Li NO
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If set to
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.Dq Li YES ,
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this option loads all available drivers.
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.It Va snd_emu10k1_load
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.Pq Dq Li NO
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If set to
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.Dq Li YES ,
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only the SoundBlaster 5.1 driver and dependent modules will be loaded.
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.It Va snd_foo_load
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.Pq Dq Li NO
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If set to
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.Dq Li YES ,
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load driver for card/chipset foo.
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.El
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.Pp
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To define default values for the different mixer channels,
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set the channel to the prefered value using hints, e.g.:
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.Va hint.pcm.0.line Ns = Ns Qq Li 0 .
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This will mute the input channel per default.
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.Ss VCHANs
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Each device can optionally support more playback channels
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that physical hardware provides by using
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.Dq virtual channels
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or
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.Tn VCHANs .
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.Tn VCHAN
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options can be configured via the
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.Xr sysctl 8
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interface but can only be manipulated while the device is inactive.
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.Ss Runtime Configuration
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The following
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.Xr sysctl 8
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variables are available:
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.Bl -tag -width ".Va hw.snd.report_soft_formats" -offset indent
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.It Va hw.snd.pcm%d.buffersize
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Configure the amount of
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.Tn DMA
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bufferspace available for a device.
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.It Va hw.snd.targetirqrate
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Set the default block size such that continuous
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playback will achieve this
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.Tn IRQ
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rate.
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This value can be tuned to improve application performance.
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Increase this value when the sound lags and decrease
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it if sound stutters or breaks up.
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.It Va hw.snd.unit
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When using
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.Xr devfs 5 ,
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the default device for
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.Pa /dev/dsp .
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Equivalent to a symlink from
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.Pa /dev/dsp
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to
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.Pa /dev/dsp Ns Va ${hw.snd.unit} .
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.It Va hw.snd.report_soft_formats
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Controls the internal format conversion if it is
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available transparently to the application software.
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When disabled or not available, the application will
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only be able to select formats the device natively supports.
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.It Va hw.snd.verbose
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Level of verbosity for the
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.Pa /dev/sndstat
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device.
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Higher values include more output and the highest level,
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three, should be used when reporting problems.
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Other options include:
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.Bl -tag -width 2n
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.It 0
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Installed devices and their allocated bus resources.
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.It 1
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The number of playback, record, virtual channels, and
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flags per device.
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.It 2
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Channel information per device including the channel's
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current format, speed, and pseudo device statistics such as
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buffer overruns and buffer underruns.
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.It 3
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File names and versions of the currently sound loaded modules.
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.El
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.It Va hw.snd.maxautovchans
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Global
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.Tn VCHAN
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setting that only affects devices that have only one playback channel.
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The sound system will dynamically create up this many
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.Tn VCHANs .
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Set to
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.Dq 0
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if no
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.Tn VCHANS
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are desired.
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.It Va hw.snd.pcm%d.vchans
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The current number of
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.Tn VCHANs
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allocated per device.
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This can be set to preallocate a certain number of
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.Tn VCHANs .
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Setting this value to
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.Dq 0
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will disable
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.Tn VCHANs
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for this device.
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.El
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.Ss Recording Channels
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On devices that have more than one recording source (ie: mic and line),
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there is a corresponding
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.Pa /dev/dspr%d.%d
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device.
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.Ss Statistics
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Channel statistics are only kept while the device is open.
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So with situations involving overruns and underruns, consider the output
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while the errant application is open and running.
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.Ss IOCTL Support
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The driver supports most of the
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.Tn OSS
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.Fn ioctl
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functions, and most applications work unmodified.
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A few differences exist, while memory mapped playback is
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supported natively and in
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.Tn Linux
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emulation, memory mapped recording is
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not due to
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.Tn VM
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system design.
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As a consequence, some applications may need to be recompiled
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with a slightly modified audio module.
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See
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.In sys/soundcard.h
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for a complete list of the supported
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.Fn ioctl
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functions.
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.Ss Supported Cards
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Below we include a list of supported codecs/cards.
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If your sound card
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is not listed here, it may be supported by a bridge driver.
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.Bl -tag -width 2m
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.It CS4237, CS4236, CS4232, CS4231 (ISA)
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All these cards work perfectly in full duplex using the MSS mode.
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This chipset is used, among others, on the A/Open AW35 and AW32, on
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some Intel motherboards, and (the CS4231) on some non-PnP cards.
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.Pp
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The CS4232 is reported as buggy in the Voxware documentation but
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I am not sure if this is true.
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On one of my Intel motherboards,
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capture does not work simply because the capture DMA channel is
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not wired to the ISA DMA controller.
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.It Yamaha OPL-SAx (ISA)
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Works perfectly in all modes.
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This chip is used in several PnP cards,
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but also (in non-PnP mode) on motherboards and laptops (e.g., the
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Toshiba Libretto).
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.It OPTi931 (ISA)
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The chip is buggy, but the driver has many workarounds to make it work
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in full duplex because for some time these were the only full duplex
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cards I could find.
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U-law format uses U8 format internally because of
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a bug in the chip.
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.It Trident 4DWave DX/NX (PCI)
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.It ENSONIQ AudioPCI ES1370/1371 (PCI)
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Creative Labs SoundBlaster PCI is supported as well.
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.It ESS Solo-1/1E (PCI)
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.It NeoMagic 256AV/ZX (PCI)
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.El
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.Sh FILES
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The
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.Nm
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drivers may create the following
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device nodes:
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.Pp
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.Bl -tag -width ".Pa /dev/audio%d.%d" -compact
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.It Pa /dev/audio%d.%d
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Sparc-compatible audio device.
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.It Pa /dev/dsp%d.%d
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Digitized voice device.
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.It Pa /dev/dspW%d.%d
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Like
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.Pa /dev/dsp ,
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but 16 bits per sample.
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.It Pa /dev/dspr%d.%d
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Should be connected to a record codec.
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.It Pa /dev/sndstat
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Current
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.Nm
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status, including all channels and drivers.
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.El
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.Pp
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The first number in the device node
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represents the unit number of the
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.Nm
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device.
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All
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.Nm
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devices are listed
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in
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.Pa /dev/sndstat .
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Additional messages are sometimes recorded when the
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device is probed and attached, these messages can be viewed with the
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.Xr dmesg 8
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utility.
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.Sh DIAGNOSTICS
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.Bl -diag
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.It ac97: dac not ready
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AC97 codec is not likely to be accompanied with the sound card.
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.It unsupported subdevice XX
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A device node is not created properly.
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.El
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.Sh BUGS
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Some features of your cards (e.g., global volume control) might not
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be supported on all devices.
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.Sh HISTORY
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The
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.Nm
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device driver first appeared in
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.Fx 2.2.6
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as
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.Nm pcm ,
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written by
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.An Luigi Rizzo .
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It was later
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rewritten in
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.Fx 4.0
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by
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.An Cameron Grant .
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The API evolved from the VOXWARE
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standard which later became OSS standard.
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.Sh SEE ALSO
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.Xr snd_csa 4 ,
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.Xr snd_gusc 4 ,
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.Xr snd_sbc 4 ,
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.Xr devfs 5 ,
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.Xr loader.conf 5 ,
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.Xr dmesg 8 ,
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.Xr kldload 8 ,
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.Xr sysctl 8
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.Rs
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.%T "The OSS API"
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.%O "http://www.opensound.com/pguide/oss.pdf"
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.Re
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.Sh AUTHORS
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.An -nosplit
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.An Luigi Rizzo Aq luigi@iet.unipi.it
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initially wrote the
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.Nm pcm
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device driver and this manual page.
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.An Cameron Grant Aq gandalf@vilnya.demon.co.uk
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later revised the device driver for
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.Fx 4.0 .
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.An Seigo Tanimura Aq tanimura@r.dl.itc.u-tokyo.ac.jp
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revised this manual page.
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It was then rewritten for
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.Fx 5.2 .
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