1.\" 2.\" Copyright (c) 1998, Luigi Rizzo 3.\" All rights reserved. 4.\" 5.\" Redistribution and use in source and binary forms, with or without 6.\" modification, are permitted provided that the following conditions 7.\" are met: 8.\" 1. Redistributions of source code must retain the above copyright 9.\" notice, this list of conditions and the following disclaimer. 10.\" 2. Redistributions in binary form must reproduce the above copyright 11.\" notice, this list of conditions and the following disclaimer in the 12.\" documentation and/or other materials provided with the distribution. 13.\" 14.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24.\" SUCH DAMAGE. 25.\" 26.\" $FreeBSD: src/share/man/man4/pcm.4,v 1.12.2.11 2002/12/12 19:53:32 trhodes Exp $ 27.\" 28.Dd June 3, 1998 29.Dt PCM 4 30.Os 31.Sh NAME 32.Nm pcm , 33.Nm snd 34.Nd FreeBSD PCM audio device driver 35.Sh SYNOPSIS 36For a card with bridge driver support, and a PnP card: 37.Cd "device pcm" 38.Pp 39For a card without bridge driver support, and a non-PnP card: 40.Cd "device pcm0 at isa? port? irq 5 drq 1 flags 0x15" 41.Sh DESCRIPTION 42The 43.Nm 44driver provides support for PCM audio play and capture. 45This driver 46also supports various PCI and WSS/MSS compatible ISA sound cards, and 47AC97 mixer. 48True full duplex operation is available on most cards. 49.Pp 50If your sound card is supported by a bridge driver, 51.Nm 52driver works 53in conjunction with the bridge driver. 54.Pp 55Apart from the usual parameters, the flags field is used to specify 56the secondary DMA channel (generally used for capture in full duplex 57cards). Flags are set to 0 for cards not using a secondary DMA 58channel, or to 0x10 + C to specify channel C. 59.Pp 60The driver works best with WSS/MSS cards, which have a very clean 61architecture and an orthogonal set of features. 62They also happen to be 63among the cheapest audio cards on the market. 64.Pp 65The driver does its best to recognize the installed hardware and drive 66it correctly, so that you don't have to give too many details in the 67kernel config files. 68For PCI and ISA PnP cards this is actually easy 69since they identify themselves. 70For legacy ISA cards, the driver looks 71for MSS cards at addresses 0x530 and 0x604 (obviously, unless overridden 72in the kernel config file by specifying an address). 73.Sh IOCTL 74The driver supports most of the Voxware ioctls(), and most 75applications work unmodified (including popular mpeg players and linux 76binaries). A few 77differences exist (the most important one is the ability to use 78memory-mapped access to the audio buffers). As a consequence, some 79applications may need to be recompiled with a slightly modified 80audio module. See /usr/include/sys/soundcard.h for a complete 81list of the supported ioctls. 82.Sh SUPPORTED CARDS 83Below we include a list of supported codecs/cards. 84If your sound card 85is not listed here, it may be supported by a bridge driver. 86.Bl -tag -width 2m 87.It CS4237, CS4236, CS4232, CS4231 (ISA) 88All these cards work perfectly in full duplex using the MSS mode. 89This chipset is used, among others, on the A/Open AW35 and AW32, on 90some Intel motherboards, and (the CS4231) on some non-PnP cards. 91.Pp 92The CS4232 is reported as buggy in the Voxware documentation but 93I am not sure if this is true. 94On one of my Intel motherboards, 95capture does not work simply because the capture DMA channel is 96not wired to the ISA DMA controller. 97.It Yamaha OPL-SAx (ISA) 98Works perfectly in all modes. 99This chip is used in several PnP cards, 100but also (in non-PnP mode) on motherboards and laptops (e.g. the 101Toshiba Libretto). 102.It OPTi931 (ISA) 103The chip is buggy, but the driver has many workarounds to make it work 104in full duplex because for some time these were the only full duplex 105cards I could find. u-law formats uses U8 format internally because of 106a bug in the chip. 107.It Trident 4DWave DX/NX (PCI) 108.It ENSONIQ AudioPCI ES1370/1371 (PCI) 109Creative Labs SoundBlaster PCI is supported as well. 110.It ESS Solo-1/1E (PCI) 111.It NeoMagic 256AV/ZX (PCI) 112.El 113.Sh FILES 114The following commonly used symbolic links to real device nodes 115should be present: 116.Pp 117.Bl -tag -width /dev/sequencer -compact 118.It Pa /dev/audio 119Sparc-compatible audio device 120.It Pa /dev/dsp 121Digitized voice device 122.It Pa /dev/dspW 123Like 124.Pa /dev/dsp , 125but 16 bits per sample 126.It Pa /dev/midi 127Raw midi access device 128.It Pa /dev/mixer 129Control port mixer device 130.It Pa /dev/music 131Level 2 sequencer interface 132.It Pa /dev/sequencer 133Sequencer device 134.It Pa /dev/pss 135Programmable device interface 136.El 137.Pp 138Each symbolic link refers to a device node of the same name, 139but with a unit number appended. 140The unit number for each device matches the unit number of the 141device probed at boot time. 142Device probe messages can be examined with the 143.Xr dmesg 8 144utility. 145.Pp 146All the appropriate device nodes and symbolic links 147for the 148.Ql pcm0 149device can be created with the following commands: 150.Bd -literal -offset indent 151cd /dev; sh MAKEDEV snd0 152.Ed 153.Pp 154Similarly, the device nodes and symbolic links for the 155.Ql pcm1 156device would be created as follows: 157.Bd -literal -offset indent 158cd /dev; sh MAKEDEV snd1 159.Ed 160.Pp 161Since the 162.Pa /dev/MAKEDEV 163utility creates symbolic links that will be used by 164many utilities by default, 165the device nodes and symbolic links for the 166preferred audio device in systems with multiple audio devices 167should be created last. 168.Sh DIAGNOSTICS AND TROUBLESHOOTING 169.Bl -tag -width 2m 170.It ac97: dac not ready 171AC97 codec is not likely to be accompanied with the sound card. 172.It unsupported subdevice XX 173A device node is not created properly. 174.El 175.Sh BUGS 176Some features of your cards (e.g. global volume control) might not 177be supported on all devices. 178.Sh HISTORY 179The 180.Nm 181device driver first appeared in 182.Fx 2.2.6 , 183rewritten in 184.Fx 4.0 . 185.Sh SEE ALSO 186.Xr csa 4 , 187.Xr gusc 4 , 188.Xr sbc 4 189.Sh AUTHORS 190.An Luigi Rizzo Aq luigi@iet.unipi.it 191initially wrote the 192.Nm 193device driver and this manual page. 194.An Cameron Grant Aq gandalf@vilnya.demon.co.uk 195totally revised the device driver. 196.An Seigo Tanimura Aq tanimura@r.dl.itc.u-tokyo.ac.jp 197revised this manual page. 198