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 $
27 .\" $DragonFly: src/share/man/man4/pcm.4,v 1.3 2003/09/07 17:04:00 hmp Exp $
35 .Nd FreeBSD PCM audio device driver
37 For a card with bridge driver support, and a PnP card:
40 For a card without bridge driver support, and a non-PnP card:
41 .Cd "device pcm0 at isa? port? irq 5 drq 1 flags 0x15"
45 driver provides support for PCM audio play and capture.
47 also supports various PCI and WSS/MSS compatible ISA sound cards, and
49 True full duplex operation is available on most cards.
51 If your sound card is supported by a bridge driver,
54 in conjunction with the bridge driver.
56 Apart from the usual parameters, the flags field is used to specify
57 the secondary DMA channel (generally used for capture in full duplex
58 cards). Flags are set to 0 for cards not using a secondary DMA
59 channel, or to 0x10 + C to specify channel C.
61 The driver works best with WSS/MSS cards, which have a very clean
62 architecture and an orthogonal set of features.
63 They also happen to be
64 among the cheapest audio cards on the market.
66 The driver does its best to recognize the installed hardware and drive
67 it correctly, so that you don't have to give too many details in the
69 For PCI and ISA PnP cards this is actually easy
70 since they identify themselves.
71 For legacy ISA cards, the driver looks
72 for MSS cards at addresses 0x530 and 0x604 (obviously, unless overridden
73 in the kernel config file by specifying an address).
75 The driver supports most of the Voxware ioctls(), and most
76 applications work unmodified (including popular mpeg players and linux
78 differences exist (the most important one is the ability to use
79 memory-mapped access to the audio buffers). As a consequence, some
80 applications may need to be recompiled with a slightly modified
83 .Aq Pa sys/soundcard.h
84 for a complete list of the supported ioctls.
86 Below we include a list of supported codecs/cards.
88 is not listed here, it may be supported by a bridge driver.
90 .It CS4237, CS4236, CS4232, CS4231 (ISA)
91 All these cards work perfectly in full duplex using the MSS mode.
92 This chipset is used, among others, on the A/Open AW35 and AW32, on
93 some Intel motherboards, and (the CS4231) on some non-PnP cards.
95 The CS4232 is reported as buggy in the Voxware documentation but
96 I am not sure if this is true.
97 On one of my Intel motherboards,
98 capture does not work simply because the capture DMA channel is
99 not wired to the ISA DMA controller.
100 .It Yamaha OPL-SAx (ISA)
101 Works perfectly in all modes.
102 This chip is used in several PnP cards,
103 but also (in non-PnP mode) on motherboards and laptops (e.g. the
106 The chip is buggy, but the driver has many workarounds to make it work
107 in full duplex because for some time these were the only full duplex
108 cards I could find. u-law formats uses U8 format internally because of
110 .It Trident 4DWave DX/NX (PCI)
111 .It ENSONIQ AudioPCI ES1370/1371 (PCI)
112 Creative Labs SoundBlaster PCI is supported as well.
113 .It ESS Solo-1/1E (PCI)
114 .It NeoMagic 256AV/ZX (PCI)
117 The following commonly used symbolic links to real device nodes
120 .Bl -tag -width /dev/sequencer -compact
122 Sparc-compatible audio device
124 Digitized voice device
128 but 16 bits per sample
130 Raw midi access device
132 Control port mixer device
134 Level 2 sequencer interface
135 .It Pa /dev/sequencer
138 Programmable device interface
141 Each symbolic link refers to a device node of the same name,
142 but with a unit number appended.
143 The unit number for each device matches the unit number of the
144 device probed at boot time.
145 Device probe messages can be examined with the
149 All the appropriate device nodes and symbolic links
152 device can be created with the following commands:
153 .Bd -literal -offset indent
154 cd /dev; sh MAKEDEV snd0
157 Similarly, the device nodes and symbolic links for the
159 device would be created as follows:
160 .Bd -literal -offset indent
161 cd /dev; sh MAKEDEV snd1
166 utility creates symbolic links that will be used by
167 many utilities by default,
168 the device nodes and symbolic links for the
169 preferred audio device in systems with multiple audio devices
170 should be created last.
171 .Sh DIAGNOSTICS AND TROUBLESHOOTING
173 .It ac97: dac not ready
174 AC97 codec is not likely to be accompanied with the sound card.
175 .It unsupported subdevice XX
176 A device node is not created properly.
179 Some features of your cards (e.g. global volume control) might not
180 be supported on all devices.
184 device driver first appeared in
193 .An Luigi Rizzo Aq luigi@iet.unipi.it
196 device driver and this manual page.
197 .An Cameron Grant Aq gandalf@vilnya.demon.co.uk
198 totally revised the device driver.
199 .An Seigo Tanimura Aq tanimura@r.dl.itc.u-tokyo.ac.jp
200 revised this manual page.