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.\" $DragonFly: src/share/man/man4/pcm.4,v 1.3 2003/09/07 17:04:00 hmp Exp $ 28.\" 29.Dd June 3, 1998 30.Dt PCM 4 31.Os 32.Sh NAME 33.Nm pcm , 34.Nm snd 35.Nd FreeBSD PCM audio device driver 36.Sh SYNOPSIS 37For a card with bridge driver support, and a PnP card: 38.Cd "device pcm" 39.Pp 40For a card without bridge driver support, and a non-PnP card: 41.Cd "device pcm0 at isa? port? irq 5 drq 1 flags 0x15" 42.Sh DESCRIPTION 43The 44.Nm 45driver provides support for PCM audio play and capture. 46This driver 47also supports various PCI and WSS/MSS compatible ISA sound cards, and 48AC97 mixer. 49True full duplex operation is available on most cards. 50.Pp 51If your sound card is supported by a bridge driver, 52.Nm 53driver works 54in conjunction with the bridge driver. 55.Pp 56Apart from the usual parameters, the flags field is used to specify 57the secondary DMA channel (generally used for capture in full duplex 58cards). Flags are set to 0 for cards not using a secondary DMA 59channel, or to 0x10 + C to specify channel C. 60.Pp 61The driver works best with WSS/MSS cards, which have a very clean 62architecture and an orthogonal set of features. 63They also happen to be 64among the cheapest audio cards on the market. 65.Pp 66The driver does its best to recognize the installed hardware and drive 67it correctly, so that you don't have to give too many details in the 68kernel config files. 69For PCI and ISA PnP cards this is actually easy 70since they identify themselves. 71For legacy ISA cards, the driver looks 72for MSS cards at addresses 0x530 and 0x604 (obviously, unless overridden 73in the kernel config file by specifying an address). 74.Sh IOCTL 75The driver supports most of the Voxware ioctls(), and most 76applications work unmodified (including popular mpeg players and linux 77binaries). A few 78differences exist (the most important one is the ability to use 79memory-mapped access to the audio buffers). As a consequence, some 80applications may need to be recompiled with a slightly modified 81audio module. 82See 83.Aq Pa sys/soundcard.h 84for a complete list of the supported ioctls. 85.Sh SUPPORTED CARDS 86Below we include a list of supported codecs/cards. 87If your sound card 88is not listed here, it may be supported by a bridge driver. 89.Bl -tag -width 2m 90.It CS4237, CS4236, CS4232, CS4231 (ISA) 91All these cards work perfectly in full duplex using the MSS mode. 92This chipset is used, among others, on the A/Open AW35 and AW32, on 93some Intel motherboards, and (the CS4231) on some non-PnP cards. 94.Pp 95The CS4232 is reported as buggy in the Voxware documentation but 96I am not sure if this is true. 97On one of my Intel motherboards, 98capture does not work simply because the capture DMA channel is 99not wired to the ISA DMA controller. 100.It Yamaha OPL-SAx (ISA) 101Works perfectly in all modes. 102This chip is used in several PnP cards, 103but also (in non-PnP mode) on motherboards and laptops (e.g. the 104Toshiba Libretto). 105.It OPTi931 (ISA) 106The chip is buggy, but the driver has many workarounds to make it work 107in full duplex because for some time these were the only full duplex 108cards I could find. u-law formats uses U8 format internally because of 109a bug in the chip. 110.It Trident 4DWave DX/NX (PCI) 111.It ENSONIQ AudioPCI ES1370/1371 (PCI) 112Creative Labs SoundBlaster PCI is supported as well. 113.It ESS Solo-1/1E (PCI) 114.It NeoMagic 256AV/ZX (PCI) 115.El 116.Sh FILES 117The following commonly used symbolic links to real device nodes 118should be present: 119.Pp 120.Bl -tag -width /dev/sequencer -compact 121.It Pa /dev/audio 122Sparc-compatible audio device 123.It Pa /dev/dsp 124Digitized voice device 125.It Pa /dev/dspW 126Like 127.Pa /dev/dsp , 128but 16 bits per sample 129.It Pa /dev/midi 130Raw midi access device 131.It Pa /dev/mixer 132Control port mixer device 133.It Pa /dev/music 134Level 2 sequencer interface 135.It Pa /dev/sequencer 136Sequencer device 137.It Pa /dev/pss 138Programmable device interface 139.El 140.Pp 141Each symbolic link refers to a device node of the same name, 142but with a unit number appended. 143The unit number for each device matches the unit number of the 144device probed at boot time. 145Device probe messages can be examined with the 146.Xr dmesg 8 147utility. 148.Pp 149All the appropriate device nodes and symbolic links 150for the 151.Ql pcm0 152device can be created with the following commands: 153.Bd -literal -offset indent 154cd /dev; sh MAKEDEV snd0 155.Ed 156.Pp 157Similarly, the device nodes and symbolic links for the 158.Ql pcm1 159device would be created as follows: 160.Bd -literal -offset indent 161cd /dev; sh MAKEDEV snd1 162.Ed 163.Pp 164Since the 165.Pa /dev/MAKEDEV 166utility creates symbolic links that will be used by 167many utilities by default, 168the device nodes and symbolic links for the 169preferred audio device in systems with multiple audio devices 170should be created last. 171.Sh DIAGNOSTICS AND TROUBLESHOOTING 172.Bl -tag -width 2m 173.It ac97: dac not ready 174AC97 codec is not likely to be accompanied with the sound card. 175.It unsupported subdevice XX 176A device node is not created properly. 177.El 178.Sh BUGS 179Some features of your cards (e.g. global volume control) might not 180be supported on all devices. 181.Sh HISTORY 182The 183.Nm 184device driver first appeared in 185.Fx 2.2.6 , 186rewritten in 187.Fx 4.0 . 188.Sh SEE ALSO 189.Xr csa 4 , 190.Xr gusc 4 , 191.Xr sbc 4 192.Sh AUTHORS 193.An Luigi Rizzo Aq luigi@iet.unipi.it 194initially wrote the 195.Nm 196device driver and this manual page. 197.An Cameron Grant Aq gandalf@vilnya.demon.co.uk 198totally revised the device driver. 199.An Seigo Tanimura Aq tanimura@r.dl.itc.u-tokyo.ac.jp 200revised this manual page. 201