/[gentoo]/xml/htdocs/doc/en/alsa-guide.xml
Gentoo

Contents of /xml/htdocs/doc/en/alsa-guide.xml

Parent Directory Parent Directory | Revision Log Revision Log


Revision 1.2 - (hide annotations) (download) (as text)
Fri Nov 15 18:39:34 2002 UTC (11 years, 9 months ago) by zhen
Branch: MAIN
Changes since 1.1: +2 -2 lines
File MIME type: application/xml
changed all of the <guide link> tags so that they are current

1 drobbins 1.1 <?xml version='1.0'?>
2     <?xml-stylesheet href="/xsl/guide.xsl" type="text/xsl"?>
3    
4     <!DOCTYPE guide SYSTEM "/dtd/guide.dtd">
5    
6 zhen 1.2 <guide link = "/doc/en/alsa-guide.xml">
7 drobbins 1.1 <title>Gentoo Linux ALSA Guide</title>
8     <author title="Author"><mail link="zu@pandora.be">
9     Vincent Verleye</mail>
10     </author>
11    
12     <author title="Editor"><mail link="zhen@gentoo.org">
13     John P. Davis</mail>
14     </author>
15    
16     <abstract>
17     This guide will show you how to set up the Advanced Linux Sound Architecture (ALSA) on Gentoo Linux.
18     In addition to the Gentoo Linux Desktop Configuration Guide, this guide is supposed to give you more information on this subject. </abstract>
19    
20     <version>1.0</version>
21     <date>30 Oct 2002</date>
22    
23     <chapter>
24     <title>Introduction</title>
25     <section>
26     <title>What is ALSA?</title>
27     <body>
28     <p>
29     The Advanced Linux Sound Architecture (ALSA) is a project to improve the Linux sound subsystem by rewriting
30     large chunks of it.
31     It is anticipated that ALSA will make it into Linux kernel 2.6.x (or 3.x.x -- whichever comes first) as it becomes ready.
32     </p>
33    
34     <p>
35     ALSA provides audio and MIDI functionality for Linux.
36     </p>
37    
38     <p>
39     Quoted from <uri>http://www.alsa-project.org</uri>, ALSA has the following features:
40     <ul><li> Efficient support for all types of audio interfaces, from consumer soundcards to professional multichannel audio interfaces.</li>
41     <li> Fully modularized sound drivers.</li>
42     <li> SMP and thread-safe design.</li>
43     <li> User space library (alsa-lib) to simplify application programming and provide higher level functionality.</li>
44     <li> Support for the older OSS API, providing binary compatibility for most OSS programs.</li>
45     </ul>
46     There's lots more to ALSA however, like support for Full Duplex playback and recording, multiple soundcard support,
47     hardware mixing of streams, extensive mixer capabilities (to support advanced features of new soundcards), ...
48     </p>
49     </body>
50     </section>
51     <section>
52     <title>Why use ALSA?</title>
53     <body>
54     <p>
55     If your soundcard is supported by the Linux kernel sound system or the commercial OSS/4Front sound driver system,
56     which can be found in all 2.4.x Linux kernels, you could just aswell build <e>those modules</e> for use with your soundcard.
57     If you want this, just read through the <uri link="http://www.tldp.org/HOWTO/Sound-HOWTO/index.html">Linux Sound HOWTO</uri>.
58     </p>
59     <p>
60     However, those OSS/4Front drivers have some limitations -- being commercial is one.
61     ALSA is an attempt to go beyond these limitations and to do so in an open source fashion.
62     ALSA is a fully GPL and LGPL'ed sound driver system, that provides a professional quality system for recording, playback,
63     and MIDI sequencing.
64     </p>
65     </body>
66     </section>
67     <section>
68     <title>What cards does ALSA support?</title>
69     <body>
70     <p>
71     ALSA tries to support as many (new) cards as possible by providing open-source drivers.
72     However, some vendors may provide binary-only packages.
73     </p>
74     <p>To know if your card is supported, you can find a Soundcard Matrix of supported and not-supported cards here:
75     <uri>http://www.alsa-project.org/alsa-doc/</uri>.
76     </p>
77     </body>
78     </section>
79     </chapter>
80    
81     <chapter>
82     <title>Installation</title>
83     <section>
84     <title>Kernel modules</title>
85     <body>
86     <p>
87     Since we're still using 2.4.x kernel sources, we'll have to compile kernel modules and ALSA modules separately.
88     </p>
89     <p>
90     First we'll make sure that our kernel configuration is ready for use with ALSA.
91     All you need in your kernel configuration is having Sound Card Support set to be built as a module (M).
92     This will build <c>soundcore.o</c>.
93     </p>
94     <p>
95     <note>
96     Possibly, this will also work when you built Sound Card Support in the kernel (Y) instead of building it as a module (M).
97     However, the official ALSA documentation suggests building it as a module, since ALSA will try loading it.
98     </note>
99     </p>
100     <p>If you already have a working kernel configuration, make sure you remove all sound drivers (except for Sound Card Support).
101     If you wish to do this without having to reboot, you could do like this:
102     </p>
103     <pre>
104     # <c>cd /usr/src/linux</c>
105     # <c>cp .config ~</c>
106     # <c>make mrproper</c>
107     # <c>cp ~/.config .</c>
108     # <c>make menuconfig</c>
109     </pre>
110     <p>
111     Now select <e>Sound Card Support</e> as Module (M) and deselect all other sound drivers.
112     Exit and say Y to save your kernel configuration.
113     After that, build the modules:
114     </p>
115     <pre>
116     # <c>make dep clean</c>
117     # <c>make modules modules_install</c>
118     </pre>
119     <p>
120     Before installing your new modules, this last line will delete all your previous modules,
121     even the ones from a previous ALSA installation.
122     </p>
123     <p>
124     <impo>
125     This means, whenever you recompile your kernel later on, you MUST recompile <c>alsa-driver</c>.
126     </impo>
127     </p>
128     <p>
129     <note>However, there's no need to reinstall <c>nvidia-kernel</c>, the Nvidia drivers are in a separate directory
130     in <path>/lib/modules/*/video</path> and won't get deleted by a <c>make modules modules_install</c>
131     </note>
132     </p>
133     </body>
134     </section>
135    
136     <section>
137     <title>ALSA modules</title>
138     <body>
139    
140     <p>
141     Now it's time to install the ALSA drivers for your soundcard(s). If your soundcard is PCI, you can find out the name
142     and type of your soundcard by looking at the output of /proc/pci
143     <pre>#<c>cat /proc/pci | grep audio</c></pre>
144     </p>
145    
146     <p>
147     <warn>
148     If you had a previous sound setup and there are still non-ALSA sound modules loaded, unload them <e>now</e>.
149     Check with <c>lsmod</c> and use <c>rmmod</c> to unload all sound-related modules on your system.
150     </warn>
151     </p>
152    
153     <p>
154     We could simply do an <c>emerge alsa-driver</c> now, this would compile and install <e>all</e> ALSA sound drivers.
155     </p>
156     <p>
157     However, to save some time, lookup the <e>Module Name</e> of your soundcard(s) on the
158     <uri link="http://www.alsa-project.org/alsa-doc">ALSA Soundcard Matrix</uri> under the <e>Install</e> section.
159     Mine is <c>EMU10K1</c>, since I have an SBlive! soundcard.
160     We'll set ALSA_CARDS environment to this value before emerging, so emerge will only compile the drivers we need.
161     </p>
162    
163     <p>
164     <pre>
165     # <c>env ALSA_CARDS='emu10k1' emerge alsa-driver</c>
166     </pre>
167     </p>
168     <p>
169     <note>
170     When you want to install ALSA drivers for more than one soundcard, you could set ALSA_CARDS to a space-separated list
171     of drivers; like this: <c>env ALSA_CARDS='emu10k1 intel8x0 ens1370' emerge alsa-driver</c>
172     </note>
173    
174     <note>If you want to have OSS compatibility, make sure to emerge <i>alsa-oss</i>, it is the ALSA/OSS compatibility
175     wrapper. </note>
176    
177     </p>
178     <p>
179     After this, the ALSA modules should be installed on your system.
180     </p>
181     </body>
182     </section>
183     <section>
184     <title>Configuration of ALSA</title>
185     <body>
186     <p>
187     Let's start configuring now to get ALSA working properly.
188     We'll need to edit some files, to let our system know about the freshly installed ALSA modules.
189     </p>
190     <p>
191     First file to edit is <path>/etc/modules.d/alsa</path>.
192     </p>
193     <warn>
194     There is no need to edit <path>/etc/modules.conf</path>. Instead, always edit files in <path>/etc/modules.d</path>.
195     </warn>
196     <p>
197     Check the ALSA portion <e>at the top of the file</e>.
198     By adding this line you can specify the max number of soundcards you have (generally, just one).
199     </p>
200     <p>
201     <pre caption="At the top of /etc/modules.d/alsa">
202     # Alsa 0.9.X kernel modules' configuration file.
203 zhen 1.2 # $Header: /home/cvsroot/gentoo-src/gentoo-xml/htdocs/doc/en/alsa-guide.xml,v 1.1 2002/11/09 18:47:44 drobbins Exp $
204 drobbins 1.1
205     # ALSA portion
206     alias char-major-116 snd
207     <c>options snd snd_major=116 snd_cards_limit=1</c>
208     # OSS/Free portion
209     alias char-major-14 soundcore
210    
211     ##
212     ## IMPORTANT:
213     </pre>
214     </p>
215     <p>
216     Now we'll specify the sounddriver(s) ALSA should use. In the same file, edit like this:
217     <pre caption="A bit lower in /etc/modules.d/alsa">
218     ## and then run `update-modules' command.
219     ## Read alsa-driver's INSTALL file in /usr/share/doc for more info.
220     ##
221     ## ALSA portion
222     <c>alias snd-card-0 snd-emu10k1</c>
223     <c>## If you have more than one, add:
224     ## alias snd-card-1 snd-intel8x0
225     ## alias snd-card-2 snd-ens1370</c>
226     ## OSS/Free portion
227     ## alias sound-slot-0 snd-card-0
228     ## alias sound-slot-1 snd-card-1
229     ##
230     </pre>
231     </p>
232     <p>
233     <note>
234     If you have more than one soundcard, adjust the <c>snd_cards_limit</c> value and add more snd-card aliases to the file.
235     I don't have experience with this, but you can find examples for configurations with two or more soundcards in
236     <uri link="http://www.alsa-project.org/alsa-doc/alsa-howto/c1660.htm">Chapter 6</uri>
237     of the <uri link="http://www.alsa-project.org/alsa-doc/alsa-howto/alsa-howto.html">ALSA Howto</uri>.
238     </note>
239     </p>
240     <p>
241     Last thing to do in this file, at the very bottom, check if these lines are there and uncommented:
242     <pre caption="at the very bottom of /etc/modules.d/alsa">
243     alias /dev/mixer snd-mixer-oss
244     alias /dev/dsp snd-pcm-oss
245     alias /dev/midi snd-seq-oss
246     </pre>
247     </p>
248     <p>
249     Now double-check the file <path>/etc/modules.d/alsa</path> and when you're sure everyting is ok, run <c>update-modules</c>.
250     <pre>
251     # <c>update-modules</c>
252     </pre>
253     </p>
254     <note>
255     Running <c>update-modules</c> here will insert the data from <path>/etc/modules.d/alsa</path> into <path>/etc/modules.conf</path>
256     </note>
257     <p>
258     You should also verify that /etc/devfsd.conf has the alsa devices and permissions correctly registered.
259     </p>
260     <pre>
261     # nano -w /etc/devfsd.conf
262     </pre>
263     <pre>
264     # ALSA/OSS stuff
265     # Comment/change these if you want to change the permissions on
266     # the audio devices
267     LOOKUP snd MODLOAD ACTION snd
268     LOOKUP dsp MODLOAD
269     LOOKUP mixer MODLOAD
270     LOOKUP midi MODLOAD
271     REGISTER sound/.* PERMISSIONS root.audio 660
272     REGISTER snd/.* PERMISSIONS root.audio 660
273     </pre>
274     <note>
275     Notice that devfsd.conf sets /dev/sound permissions to be root.audio. Thus, for non-root users to use audio they will have to be part of the audio group.
276     </note>
277     </body>
278     </section>
279     </chapter>
280     <chapter>
281     <title>Starting ALSA</title>
282     <section>
283     <title>Adding alsasound to a runlevel</title>
284     <body>
285     <p>
286     First thing to do now, is to make ALSA startup at boottime. Like this:
287     <pre>
288     # <c>rc-update add alsasound boot</c>
289     </pre>
290     </p>
291     <p>
292     <warn>Note that the alsasound script should be added to the "boot" runlevel, not the "default" runlevel.</warn>
293     </p>
294     </body>
295     </section>
296     <section>
297     <title>Running and unmuting</title>
298     <body>
299     <p>
300     Since we're Linux users, we don't want to reboot. So we'll start the alsasound script manually.
301     </p>
302     <pre>
303     # <c>/etc/init.d/alsasound start</c>
304     </pre>
305     <p>
306     ALSA is running now. If everything is ok, you should be able to see the ALSA modules loaded when running <c>lsmod</c>.
307     However, sound won't work yet, because the channels are still muted. We need <c>alsa-utils</c> for this.
308     </p>
309     <pre>
310     # <c>emerge alsa-utils</c>
311     # <c>amixer</c>
312     </pre>
313     <p>
314     <warn>
315     You shouldn't get this, but <e>if</e> you get an error about "amixer: Mixer attach default error: No such file or directory", you should manually insmod
316     <c>snd-mixer-oss</c> and <c>snd-pcm-oss</c> once. After that run amixer again.
317     </warn>
318     </p>
319     <pre caption="only if you get an error when running amixer">
320     # <c>insmod snd-mixer-oss</c>
321     # <c>insmod snd-pcm-oss</c>
322     # <c>amixer</c>
323     </pre>
324     <p>
325     If you got this far, now unmute both Master and PCM channels.
326     </p>
327     <p>
328     <pre>
329     # <c>amixer set Master 100 unmute</c>
330     # <c>amixer set PCM 100 unmute</c>
331     # <c>aplay /usr/kde/3/share/sounds/pop.wav</c> <codenote>(pop.wav is part of KDE)</codenote>
332     </pre>
333     </p>
334     We check to see if sound is working by using the aplay (alsa play) command. If you hear a pop, then sound is indeed working.
335     Then, adjust the volume settings to your liking; the ncurses-based <c>alsamixer</c> is a great way to get them "just so".
336     <p>
337     You may want to emerge <c>alsa-xmms</c> as that will provide ALSA support for XMMS.
338     </p>
339     When you reboot your system, the <e>alsasound</e> init script will properly save and restore your volume settings.
340     </body>
341     </section>
342     </chapter>
343     <chapter>
344     <title>Final Notes</title>
345     <section>
346     <title>After kernel-upgrades..</title>
347     <body>
348     <p>When you ever rebuild your kernel, or upgrade to another kernel, you'll have to rebuild the ALSA modules.</p>
349     <p>Although you might have installed <c>alsa-driver</c>, <c>alsa-libs</c> and <c>alsa-utils</c>, only the first will
350     have to be installed again, since it will put the alsa modules in
351     <path>/lib/modules/*/kernel/sound/pci/</path>.</p>
352     <pre caption="needed after each kernel compile">
353     emerge alsa-driver
354     </pre>
355     </body>
356     </section>
357     <section>
358     <title>/etc/modules.autoload</title>
359     <body>
360     <p>You won't have to edit this file for use with ALSA. After our <c>rc-update add alsasound boot</c>, our system will
361     load the correct modules at startup.</p>
362     <p>It's not necessary to add <c>snd-pcm-oss</c> or <c>snd-mixer-oss</c> in this file.
363     Check the <uri link="http://www.djcj.org/LAU/guide/alsbook/faq1.html">this FAQ</uri> for more info.</p>
364     </body>
365     </section>
366     <section>
367     <title>More links..</title>
368     <body>
369     <p>
370     You could check these for additional info:
371     </p>
372     <p>
373     <ul>
374     <li><uri link="http://www.gentoo.org/doc/desktop.html">The Gentoo Linux Desktop Configuration Guide</uri></li>
375     <li><uri link="http://www.alsa-project.org">ALSA Project Homepage</uri></li>
376     <li><uri link="http://www.alsa-project.org/documentation.php3">ALSA Users Documentation</uri></li>
377     <li><uri link="http://www.djcj.org">ALSA Howto's and FAQ's</uri></li>
378     <li><uri link="http://tldp.org/HOWTO/Sound-HOWTO/index.html">Linux Sound HOWTO</uri></li>
379     <li><uri link="http://linux-sound.org/">Sound and MIDI Software For Linux</uri></li>
380     </ul>
381     </p>
382     </body>
383     </section>
384     </chapter>
385     </guide>

  ViewVC Help
Powered by ViewVC 1.1.20