diff options
Diffstat (limited to 'kernel/Documentation/sound/oss/Introduction')
| -rw-r--r-- | kernel/Documentation/sound/oss/Introduction | 459 |
1 files changed, 459 insertions, 0 deletions
diff --git a/kernel/Documentation/sound/oss/Introduction b/kernel/Documentation/sound/oss/Introduction new file mode 100644 index 000000000..42da2d8fa --- /dev/null +++ b/kernel/Documentation/sound/oss/Introduction @@ -0,0 +1,459 @@ +Introduction Notes on Modular Sound Drivers and Soundcore +Wade Hampton +2/14/2001 + +Purpose: +======== +This document provides some general notes on the modular +sound drivers and their configuration, along with the +support modules sound.o and soundcore.o. + +Note, some of this probably should be added to the Sound-HOWTO! + +Note, soundlow.o was present with 2.2 kernels but is not +required for 2.4.x kernels. References have been removed +to this. + + +Copying: +======== +none + + +History: +======== +0.1.0 11/20/1998 First version, draft +1.0.0 11/1998 Alan Cox changes, incorporation in 2.2.0 + as Documentation/sound/oss/Introduction +1.1.0 6/30/1999 Second version, added notes on making the drivers, + added info on multiple sound cards of similar types,] + added more diagnostics info, added info about esd. + added info on OSS and ALSA. +1.1.1 19991031 Added notes on sound-slot- and sound-service. + (Alan Cox) +1.1.2 20000920 Modified for Kernel 2.4 (Christoph Hellwig) +1.1.3 20010214 Minor notes and corrections (Wade Hampton) + Added examples of sound-slot-0, etc. + + +Modular Sound Drivers: +====================== + +Thanks to the GREAT work by Alan Cox (alan@lxorguk.ukuu.org.uk), + +[And Oleg Drokin, Thomas Sailer, Andrew Veliath and more than a few + others - not to mention Hannu's original code being designed well + enough to cope with that kind of chopping up](Alan) + +the standard Linux kernels support a modular sound driver. From +Alan's comments in linux/drivers/sound/README.FIRST: + + The modular sound driver patches were funded by Red Hat Software + (www.redhat.com). The sound driver here is thus a modified version of + Hannu's code. Please bear that in mind when considering the appropriate + forums for bug reporting. + +The modular sound drivers may be loaded via insmod or modprobe. +To support all the various sound modules, there are two general +support modules that must be loaded first: + + soundcore.o: Top level handler for the sound system, provides + a set of functions for registration of devices + by type. + + sound.o: Common sound functions required by all modules. + +For the specific sound modules (e.g., sb.o for the Soundblaster), +read the documentation on that module to determine what options +are available, for example IRQ, address, DMA. + +Warning, the options for different cards sometime use different names +for the same or a similar feature (dma1= versus dma16=). As a last +resort, inspect the code (search for module_param). + +Notes: + +1. There is a new OpenSource sound driver called ALSA which is + currently under development: http://www.alsa-project.org/ + The ALSA drivers support some newer hardware that may not + be supported by this sound driver and also provide some + additional features. + +2. The commercial OSS driver may be obtained from the site: + http://www.opensound.com. This may be used for cards that + are unsupported by the kernel driver, or may be used + by other operating systems. + +3. The enlightenment sound daemon may be used for playing + multiple sounds at the same time via a single card, eliminating + some of the requirements for multiple sound card systems. For + more information, see: http://www.tux.org/~ricdude/EsounD.html + The "esd" program may be used with the real-player and mpeg + players like mpg123 and x11amp. The newer real-player + and some games even include built-in support for ESD! + + +Building the Modules: +===================== + +This document does not provide full details on building the +kernel, etc. The notes below apply only to making the kernel +sound modules. If this conflicts with the kernel's README, +the README takes precedence. + +1. To make the kernel sound modules, cd to your /usr/src/linux + directory (typically) and type make config, make menuconfig, + or make xconfig (to start the command line, dialog, or x-based + configuration tool). + +2. Select the Sound option and a dialog will be displayed. + +3. Select M (module) for "Sound card support". + +4. Select your sound driver(s) as a module. For ProAudio, Sound + Blaster, etc., select M (module) for OSS sound modules. + [thanks to Marvin Stodolsky <stodolsk@erols.com>]A + +5. Make the kernel (e.g., make bzImage), and install the kernel. + +6. Make the modules and install them (make modules; make modules_install). + +Note, for 2.5.x kernels, make sure you have the newer module-init-tools +installed or modules will not be loaded properly. 2.5.x requires an +updated module-init-tools. + + +Plug and Play (PnP: +=================== + +If the sound card is an ISA PnP card, isapnp may be used +to configure the card. See the file isapnp.txt in the +directory one level up (e.g., /usr/src/linux/Documentation). + +Also the 2.4.x kernels provide PnP capabilities, see the +file NEWS in this directory. + +PCI sound cards are highly recommended, as they are far +easier to configure and from what I have read, they use +less resources and are more CPU efficient. + + +INSMOD: +======= + +If loading via insmod, the common modules must be loaded in the +order below BEFORE loading the other sound modules. The card-specific +modules may then be loaded (most require parameters). For example, +I use the following via a shell script to load my SoundBlaster: + +SB_BASE=0x240 +SB_IRQ=9 +SB_DMA=3 +SB_DMA2=5 +SB_MPU=0x300 +# +echo Starting sound +/sbin/insmod soundcore +/sbin/insmod sound +# +echo Starting sound blaster.... +/sbin/insmod uart401 +/sbin/insmod sb io=$SB_BASE irq=$SB_IRQ dma=$SB_DMA dma16=$SB_DMA2 mpu_io=$SB_MP + +When using sound as a module, I typically put these commands +in a file such as /root/soundon.sh. + + +MODPROBE: +========= + +If loading via modprobe, these common files are automatically loaded when +requested by modprobe. For example, my /etc/modprobe.d/oss.conf contains: + +alias sound sb +options sb io=0x240 irq=9 dma=3 dma16=5 mpu_io=0x300 + +All you need to do to load the module is: + + /sbin/modprobe sb + + +Sound Status: +============= + +The status of sound may be read/checked by: + cat (anyfile).au >/dev/audio + +[WWH: This may not work properly for SoundBlaster PCI 128 cards +such as the es1370/1 (see the es1370/1 files in this directory) +as they do not automatically support uLaw on /dev/audio.] + +The status of the modules and which modules depend on +which other modules may be checked by: + /sbin/lsmod + +/sbin/lsmod should show something like the following: + sb 26280 0 + uart401 5640 0 [sb] + sound 57112 0 [sb uart401] + soundcore 1968 8 [sb sound] + + +Removing Sound: +=============== + +Sound may be removed by using /sbin/rmmod in the reverse order +in which you load the modules. Note, if a program has a sound device +open (e.g., xmixer), that module (and the modules on which it +depends) may not be unloaded. + +For example, I use the following to remove my Soundblaster (rmmod +in the reverse order in which I loaded the modules): + +/sbin/rmmod sb +/sbin/rmmod uart401 +/sbin/rmmod sound +/sbin/rmmod soundcore + +When using sound as a module, I typically put these commands +in a script such as /root/soundoff.sh. + + +Removing Sound for use with OSS: +================================ + +If you get really stuck or have a card that the kernel modules +will not support, you can get a commercial sound driver from +http://www.opensound.com. Before loading the commercial sound +driver, you should do the following: + +1. remove sound modules (detailed above) +2. remove the sound modules from /etc/modprobe.d/*.conf +3. move the sound modules from /lib/modules/<kernel>/misc + (for example, I make a /lib/modules/<kernel>/misc/tmp + directory and copy the sound module files to that + directory). + + +Multiple Sound Cards: +===================== + +The sound drivers will support multiple sound cards and there +are some great applications like multitrack that support them. +Typically, you need two sound cards of different types. Note, this +uses more precious interrupts and DMA channels and sometimes +can be a configuration nightmare. I have heard reports of 3-4 +sound cards (typically I only use 2). You can sometimes use +multiple PCI sound cards of the same type. + +On my machine I have two sound cards (cs4232 and Soundblaster Vibra +16). By loading sound as modules, I can control which is the first +sound device (/dev/dsp, /dev/audio, /dev/mixer) and which is +the second. Normally, the cs4232 (Dell sound on the motherboard) +would be the first sound device, but I prefer the Soundblaster. +All you have to do is to load the one you want as /dev/dsp +first (in my case "sb") and then load the other one +(in my case "cs4232"). + +If you have two cards of the same type that are jumpered +cards or different PnP revisions, you may load the same +module twice. For example, I have a SoundBlaster vibra 16 +and an older SoundBlaster 16 (jumpers). To load the module +twice, you need to do the following: + +1. Copy the sound modules to a new name. For example + sb.o could be copied (or symlinked) to sb1.o for the + second SoundBlaster. + +2. Make a second entry in /etc/modprobe.d/*conf, for example, + sound1 or sb1. This second entry should refer to the + new module names for example sb1, and should include + the I/O, etc. for the second sound card. + +3. Update your soundon.sh script, etc. + +Warning: I have never been able to get two PnP sound cards of the +same type to load at the same time. I have tried this several times +with the Soundblaster Vibra 16 cards. OSS has indicated that this +is a PnP problem.... If anyone has any luck doing this, please +send me an E-MAIL. PCI sound cards should not have this problem.a +Since this was originally release, I have received a couple of +mails from people who have accomplished this! + +NOTE: In Linux 2.4 the Sound Blaster driver (and only this one yet) +supports multiple cards with one module by default. +Read the file 'Soundblaster' in this directory for details. + + +Sound Problems: +=============== + +First RTFM (including the troubleshooting section +in the Sound-HOWTO). + +1) If you are having problems loading the modules (for + example, if you get device conflict errors) try the + following: + + A) If you have Win95 or NT on the same computer, + write down what addresses, IRQ, and DMA channels + those were using for the same hardware. You probably + can use these addresses, IRQs, and DMA channels. + You should really do this BEFORE attempting to get + sound working! + + B) Check (cat) /proc/interrupts, /proc/ioports, + and /proc/dma. Are you trying to use an address, + IRQ or DMA port that another device is using? + + C) Check (cat) /proc/isapnp + + D) Inspect your /var/log/messages file. Often that will + indicate what IRQ or IO port could not be obtained. + + E) Try another port or IRQ. Note this may involve + using the PnP tools to move the sound card to + another location. Sometimes this is the only way + and it is more or less trial and error. + +2) If you get motor-boating (the same sound or part of a + sound clip repeated), you probably have either an IRQ + or DMA conflict. Move the card to another IRQ or DMA + port. This has happened to me when playing long files + when I had an IRQ conflict. + +3. If you get dropouts or pauses when playing high sample + rate files such as using mpg123 or x11amp/xmms, you may + have too slow of a CPU and may have to use the options to + play the files at 1/2 speed. For example, you may use + the -2 or -4 option on mpg123. You may also get this + when trying to play mpeg files stored on a CD-ROM + (my Toshiba T8000 PII/366 sometimes has this problem). + +4. If you get "cannot access device" errors, your /dev/dsp + files, etc. may be set to owner root, mode 600. You + may have to use the command: + chmod 666 /dev/dsp /dev/mixer /dev/audio + +5. If you get "device busy" errors, another program has the + sound device open. For example, if using the Enlightenment + sound daemon "esd", the "esd" program has the sound device. + If using "esd", please RTFM the docs on ESD. For example, + esddsp <program> may be used to play files via a non-esd + aware program. + +6) Ask for help on the sound list or send E-MAIL to the + sound driver author/maintainer. + +7) Turn on debug in drivers/sound/sound_config.h (DEB, DDB, MDB). + +8) If the system reports insufficient DMA memory then you may want to + load sound with the "dmabufs=1" option. Or in /etc/conf.modules add + + preinstall sound dmabufs=1 + + This makes the sound system allocate its buffers and hang onto them. + + You may also set persistent DMA when building a 2.4.x kernel. + + +Configuring Sound: +================== + +There are several ways of configuring your sound: + +1) On the kernel command line (when using the sound driver(s) + compiled in the kernel). Check the driver source and + documentation for details. + +2) On the command line when using insmod or in a bash script + using command line calls to load sound. + +3) In /etc/modprobe.d/*conf when using modprobe. + +4) Via Red Hat's GPL'd /usr/sbin/sndconfig program (text based). + +5) Via the OSS soundconf program (with the commercial version + of the OSS driver. + +6) By just loading the module and let isapnp do everything relevant + for you. This works only with a few drivers yet and - of course - + only with isapnp hardware. + +And I am sure, several other ways. + +Anyone want to write a linuxconf module for configuring sound? + + +Module Loading: +=============== + +When a sound card is first referenced and sound is modular, the sound system +will ask for the sound devices to be loaded. Initially it requests that +the driver for the sound system is loaded. It then will ask for +sound-slot-0, where 0 is the first sound card. (sound-slot-1 the second and +so on). Thus you can do + +alias sound-slot-0 sb + +To load a soundblaster at this point. If the slot loading does not provide +the desired device - for example a soundblaster does not directly provide +a midi synth in all cases then it will request "sound-service-0-n" where n +is + + 0 Mixer + + 2 MIDI + + 3, 4 DSP audio + + +For example, I use the following to load my Soundblaster PCI 128 +(ES 1371) card first, followed by my SoundBlaster Vibra 16 card, +then by my TV card: + +# Load the Soundblaster PCI 128 as /dev/dsp, /dev/dsp1, /dev/mixer +alias sound-slot-0 es1371 + +# Load the Soundblaster Vibra 16 as /dev/dsp2, /dev/mixer1 +alias sound-slot-1 sb +options sb io=0x240 irq=5 dma=1 dma16=5 mpu_io=0x330 + +# Load the BTTV (TV card) as /dev/mixer2 +alias sound-slot-2 bttv +alias sound-service-2-0 tvmixer + +pre-install bttv modprobe tuner ; modprobe tvmixer +pre-install tvmixer modprobe msp3400; modprobe tvaudio +options tuner debug=0 type=8 +options bttv card=0 radio=0 pll=0 + + +For More Information (RTFM): +============================ +1) Information on kernel modules: manual pages for insmod and modprobe. + +2) Information on PnP, RTFM manual pages for isapnp. + +3) Sound-HOWTO and Sound-Playing-HOWTO. + +4) OSS's WWW site at http://www.opensound.com. + +5) All the files in Documentation/sound. + +6) The comments and code in linux/drivers/sound. + +7) The sndconfig and rhsound documentation from Red Hat. + +8) The Linux-sound mailing list: sound-list@redhat.com. + +9) Enlightenment documentation (for info on esd) + http://www.tux.org/~ricdude/EsounD.html. + +10) ALSA home page: http://www.alsa-project.org/ + + +Contact Information: +==================== +Wade Hampton: (whampton@staffnet.com) + |