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.\" $FreeBSD$ 27.\" 28.Dd June 3, 1998 29.Dt PCM 4 30.Os FreeBSD 31.Sh NAME 32.Nm pcm 33.Nd FreeBSD audio device driver 34.Sh SYNOPSIS 35.Cd "device pcm0 at isa? port? irq 5 drq 1 flags 0x15" 36.Sh DESCRIPTION 37The 38.Nm pcm 39driver provides support for various ISA sound cards that are compatible 40with the WSS/MSS specs, or with the SBPro and SB16. Only audio 41capture/playback is supported by the driver, and true full duplex 42operation is available on most cards. 43.Pp 44Apart from the usual parameters, the flags field is used to specify 45the secondary DMA channel (generally used for capture in full duplex 46cards). Flags are set to 0 for cards not using a secondary DMA 47channel, or to 0x10 + C to specify channel C. 48.Pp 49PnP audio cards are also supported using the 50.Nm pnp 51support which is available in 52.Fx 53starting from release 2.2.6. 54See the 55.Xr pnp 4 56manpage for more information. In particular, remember that unit 57numbers for (recognized) 58PnP cards are assigned after the legacy ISA devices, and that the 59actual resources (port, irq and drq) used by the driver are read from 60the PnP configuration and not from the "device pcm0" line. 61So, if you have the following line in your kernel config file: 62.Pp 63.Cd "device pcm0 ..." 64.Pp 65your first PnP audio card will be unit #1, i.e. it will be accessible as 66.Pa /dev/audio1 , 67.Pa /dev/dsp1 , 68etc. 69Many applications default to using /dev/audio, but appropriate 70symlinks will be created as a side-effect of the the following command: 71.Pp 72.Cd cd /dev 73.Cd ./MAKEDEV snd1 74.Pp 75The driver works best with WSS/MSS cards, which have a very clean 76architecture and an orthogonal set of features. They also happen to be 77among the cheapest audio cards on the market. 78Other cards such as SB and ESS have a more complex internal 79architecture, and often no documentation available. As a consequence, 80support for these cards is slightly worse. 81.Pp 82The driver does its best to recognize the installed harware and drive 83it correctly, so that you don't have to give too many details in the 84kernel config files. For PnP cards this is actually easy since they 85identify themselves. For legacy ISA cards, the driver first looks for 86MSS cards at addresses 0x530 and 0x604, then for SB 87cards at 0x220 and 0x240 (obviously, unless overridden in the kernel 88config file by specifying an address). 89 90.Sh IOCTL 91The driver supports most of the Voxware ioctls(), and most 92applications work unmodified (including popular mpeg players and linux 93binaries). A few 94differences exist (the most important one is the ability to use 95memory-mapped access to the audio buffers). As a consequence, some 96applications may need to be recompiled with a slightly modified 97audio module. See /usr/include/machine/soundcard.h for a complete 98list of the supported ioctls. 99 100.Sh SUPPORTED CARDS 101.Pp 102Below we include a list of supported codecs/cards, including, if 103possible, the pnp configuration information where applicable 104(we give default parameters, your actual resources may vary). 105 106.Bl -tag -width 2m % begin list 107.It CS4237, CS4236, CS4232, CS4231 108.Cd "pnp 1 0 os enable port0 0x534 port2 0x220 irq0 5 drq0 1 drq1 3" 109.Pp 110All these cards work perfectly in full duplex using the MSS mode. 111This chipset is used, among others, on the A/Open AW35 and AW32, on 112some Intel motherboards, and (the CS4231) on some non-PnP cards. 113.Pp 114The CS4232 is reported as buggy in the Voxware documentation but 115I am not sure if this is true. On one of my Intel motherboards, 116capture does not work simply because the capture DMA channel is 117not wired to the ISA DMA controller. 118 119.It GUSPnP 120.Cd "pnp 1 0 os enable port0 0x220 port1 0x320 port2 0x32c irq0 5 drq0 7 drq1 5" 121.Pp 122Supported in full duplex using the MSS mode. The GUSPnP does not use a 123real CS4231, and I suspect a bug in the emulation when operating 124with mu-law format. Since the card is discontinued, I did not bother 125to include special code to set the card in "Mode3" (where mu-law is 126known to work) and rather I use U8 format internally, and do the 127conversion in software within the driver. This loses resolution, 128so you should use 16-bit modes with this card when possible. 129 130.It Yamaha OPL-SAx 131.Cd "pnp 1 0 os enable port0 0x220 port1 0x530 port2 0x388 port3 0x370 irq0 5 drq0 1 drq1 3" 132.Pp 133Works perfectly in all modes. This chip is used in several PnP cards, 134but also (in non-PnP mode) on motherboards and laptops (e.g. the 135Toshiba Libretto). 136 137.It OPTi931 138.Cd "pnp 1 1 os enable port0 0x534 port2 0x220 port3 0xe0d irq0 10 drq0 1 drq1 6" 139.Pp 140The chip is buggy, but the driver has many workarounds to make it work 141in full duplex because for some time these were the only full duplex 142cards I could find. u-law formats uses U8 format internally because of 143a bug in the chip. 144 145.It SB16, Vibra16C, and old SB16/AWExx cards 146.Cd "pnp 1 0 os enable port0 0x220 irq0 5 drq0 1 drq1 5" 147.Pp 148These codecs have limited full duplex capabilities, by doing 8-bit 149in one direction and 16-bit in the other one. The driver supports this 150mode of operation but keep in mind that it is not a supported mode of 151operation from CreativeLabs. 152 153.It Vibra16X and newer SB16/AWExx cards 154.Cd "pnp 1 0 os enable port0 0x220 irq0 5 drq0 1 drq1 3" 155.Pp 156Recently CreativeLabs has changed the codec (DSP) and the new one is 157somewhat different from the old one. The most apparent difference is 158the use of two 8-bit DMA channels, which seems to have broken our full 159duplex support. Maybe one can achieve full duplex by making use of the 160wavetable to play audio, but since this driver does not support the 161wavetable you have to stick with half duplex. 162 163.It SBPro and clones 164This is the default mode of operation for most other cards. We have 165only limited (and possibly buggy) support for them: 8-bit, half 166duplex, even if the hardware in some cases (e.g. ESS chips) might do more. 167.El 168.Pp 169.Sh DIAGNOSTICS AND TROUBLESHOOTING 170.Bl -tag -width 2m 171.It "This is XXX but LDN Y is disabled" 172.Pp 173This means that the bios has left the PnP device disabled, and you 174have to enable it manually booting with "-c" and giving the pnp 175configuration shown above. 176.It "pcmX: unit not configured, perhaps you want pcmY ?" 177This means that you are using the wrong unit. Generally this happens 178when you are using a PnP card without creating the symlinks to the 179correct unit. Re-create the symlinks (and possibly also the device 180entries) in the /dev directory to point to the right one. 181 182.It "timeout flushing dbuf_out ..." 183This means a problem in the configuration of the card (specifically, 184in the DMA channel) or (much less likely) in the driver, which has 185not recognized the card correctly. Check the DMA channel used for 186capture. 187 188.It capture does not work 189This usually happens when the input dma channel is misconfigured. 190 191.El 192.Sh BUGS 193Due to lack of documentation, 194SB16 support is not very good. Also, mixer support is not complete, 195and some features of your cards (e.g. global volume control) might not 196be supported on all devices. 197.Sh HISTORY 198The 199.Nm pcm 200device driver first appeared in 201.Fx 2.2.6 202.Sh AUTHORS 203The 204.Nm 205device driver and this manual page were written by 206.An Luigi Rizzo Aq luigi@iet.unipi.it 207