2 .\" Copyright (c) 1998, Luigi Rizzo
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26 .\" $FreeBSD: src/share/man/man4/pcm.4,v 1.12.2.11 2002/12/12 19:53:32 trhodes Exp $
34 .Nd FreeBSD PCM audio device driver
36 For a card with bridge driver support, and a PnP card:
39 For a card without bridge driver support, and a non-PnP card:
40 .Cd "device pcm0 at isa? port? irq 5 drq 1 flags 0x15"
44 driver provides support for PCM audio play and capture.
46 also supports various PCI and WSS/MSS compatible ISA sound cards, and
48 True full duplex operation is available on most cards.
50 If your sound card is supported by a bridge driver,
53 in conjunction with the bridge driver.
55 Apart from the usual parameters, the flags field is used to specify
56 the secondary DMA channel (generally used for capture in full duplex
57 cards). Flags are set to 0 for cards not using a secondary DMA
58 channel, or to 0x10 + C to specify channel C.
60 The driver works best with WSS/MSS cards, which have a very clean
61 architecture and an orthogonal set of features.
62 They also happen to be
63 among the cheapest audio cards on the market.
65 The driver does its best to recognize the installed hardware and drive
66 it correctly, so that you don't have to give too many details in the
68 For PCI and ISA PnP cards this is actually easy
69 since they identify themselves.
70 For legacy ISA cards, the driver looks
71 for MSS cards at addresses 0x530 and 0x604 (obviously, unless overridden
72 in the kernel config file by specifying an address).
74 The driver supports most of the Voxware ioctls(), and most
75 applications work unmodified (including popular mpeg players and linux
77 differences exist (the most important one is the ability to use
78 memory-mapped access to the audio buffers). As a consequence, some
79 applications may need to be recompiled with a slightly modified
80 audio module. See /usr/include/sys/soundcard.h for a complete
81 list of the supported ioctls.
83 Below we include a list of supported codecs/cards.
85 is not listed here, it may be supported by a bridge driver.
87 .It CS4237, CS4236, CS4232, CS4231 (ISA)
88 All these cards work perfectly in full duplex using the MSS mode.
89 This chipset is used, among others, on the A/Open AW35 and AW32, on
90 some Intel motherboards, and (the CS4231) on some non-PnP cards.
92 The CS4232 is reported as buggy in the Voxware documentation but
93 I am not sure if this is true.
94 On one of my Intel motherboards,
95 capture does not work simply because the capture DMA channel is
96 not wired to the ISA DMA controller.
97 .It Yamaha OPL-SAx (ISA)
98 Works perfectly in all modes.
99 This chip is used in several PnP cards,
100 but also (in non-PnP mode) on motherboards and laptops (e.g. the
103 The chip is buggy, but the driver has many workarounds to make it work
104 in full duplex because for some time these were the only full duplex
105 cards I could find. u-law formats uses U8 format internally because of
107 .It Trident 4DWave DX/NX (PCI)
108 .It ENSONIQ AudioPCI ES1370/1371 (PCI)
109 Creative Labs SoundBlaster PCI is supported as well.
110 .It ESS Solo-1/1E (PCI)
111 .It NeoMagic 256AV/ZX (PCI)
114 The following commonly used symbolic links to real device nodes
117 .Bl -tag -width /dev/sequencer -compact
119 Sparc-compatible audio device
121 Digitized voice device
125 but 16 bits per sample
127 Raw midi access device
129 Control port mixer device
131 Level 2 sequencer interface
132 .It Pa /dev/sequencer
135 Programmable device interface
138 Each symbolic link refers to a device node of the same name,
139 but with a unit number appended.
140 The unit number for each device matches the unit number of the
141 device probed at boot time.
142 Device probe messages can be examined with the
146 All the appropriate device nodes and symbolic links
149 device can be created with the following commands:
150 .Bd -literal -offset indent
151 cd /dev; sh MAKEDEV snd0
154 Similarly, the device nodes and symbolic links for the
156 device would be created as follows:
157 .Bd -literal -offset indent
158 cd /dev; sh MAKEDEV snd1
163 utility creates symbolic links that will be used by
164 many utilities by default,
165 the device nodes and symbolic links for the
166 preferred audio device in systems with multiple audio devices
167 should be created last.
168 .Sh DIAGNOSTICS AND TROUBLESHOOTING
170 .It ac97: dac not ready
171 AC97 codec is not likely to be accompanied with the sound card.
172 .It unsupported subdevice XX
173 A device node is not created properly.
176 Some features of your cards (e.g. global volume control) might not
177 be supported on all devices.
181 device driver first appeared in
190 .An Luigi Rizzo Aq luigi@iet.unipi.it
193 device driver and this manual page.
194 .An Cameron Grant Aq gandalf@vilnya.demon.co.uk
195 totally revised the device driver.
196 .An Seigo Tanimura Aq tanimura@r.dl.itc.u-tokyo.ac.jp
197 revised this manual page.