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1 zhen 1.3 <?xml version='1.0' encoding="UTF-8"?>
2 drobbins 1.1 <!DOCTYPE guide SYSTEM "/dtd/guide.dtd">
3    
4 zhen 1.2 <guide link = "/doc/en/alsa-guide.xml">
5 drobbins 1.1 <title>Gentoo Linux ALSA Guide</title>
6     <author title="Author"><mail link="zu@pandora.be">
7     Vincent Verleye</mail>
8     </author>
9    
10     <author title="Editor"><mail link="zhen@gentoo.org">
11     John P. Davis</mail>
12     </author>
13    
14     <abstract>
15     This guide will show you how to set up the Advanced Linux Sound Architecture (ALSA) on Gentoo Linux.
16     In addition to the Gentoo Linux Desktop Configuration Guide, this guide is supposed to give you more information on this subject. </abstract>
17    
18 zhen 1.4 <version>1.1</version>
19     <date>12 January 2002</date>
20 drobbins 1.1
21     <chapter>
22     <title>Introduction</title>
23     <section>
24     <title>What is ALSA?</title>
25     <body>
26     <p>
27     The Advanced Linux Sound Architecture (ALSA) is a project to improve the Linux sound subsystem by rewriting
28     large chunks of it.
29     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.
30     </p>
31    
32     <p>
33     ALSA provides audio and MIDI functionality for Linux.
34     </p>
35    
36     <p>
37     Quoted from <uri>http://www.alsa-project.org</uri>, ALSA has the following features:
38     <ul><li> Efficient support for all types of audio interfaces, from consumer soundcards to professional multichannel audio interfaces.</li>
39     <li> Fully modularized sound drivers.</li>
40     <li> SMP and thread-safe design.</li>
41     <li> User space library (alsa-lib) to simplify application programming and provide higher level functionality.</li>
42     <li> Support for the older OSS API, providing binary compatibility for most OSS programs.</li>
43     </ul>
44     There's lots more to ALSA however, like support for Full Duplex playback and recording, multiple soundcard support,
45     hardware mixing of streams, extensive mixer capabilities (to support advanced features of new soundcards), ...
46     </p>
47     </body>
48     </section>
49     <section>
50     <title>Why use ALSA?</title>
51     <body>
52     <p>
53     If your soundcard is supported by the Linux kernel sound system or the commercial OSS/4Front sound driver system,
54     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.
55     If you want this, just read through the <uri link="http://www.tldp.org/HOWTO/Sound-HOWTO/index.html">Linux Sound HOWTO</uri>.
56     </p>
57     <p>
58     However, those OSS/4Front drivers have some limitations -- being commercial is one.
59     ALSA is an attempt to go beyond these limitations and to do so in an open source fashion.
60     ALSA is a fully GPL and LGPL'ed sound driver system, that provides a professional quality system for recording, playback,
61     and MIDI sequencing.
62     </p>
63     </body>
64     </section>
65     <section>
66     <title>What cards does ALSA support?</title>
67     <body>
68     <p>
69     ALSA tries to support as many (new) cards as possible by providing open-source drivers.
70     However, some vendors may provide binary-only packages.
71     </p>
72     <p>To know if your card is supported, you can find a Soundcard Matrix of supported and not-supported cards here:
73     <uri>http://www.alsa-project.org/alsa-doc/</uri>.
74     </p>
75     </body>
76     </section>
77     </chapter>
78    
79     <chapter>
80     <title>Installation</title>
81     <section>
82     <title>Kernel modules</title>
83     <body>
84     <p>
85     Since we're still using 2.4.x kernel sources, we'll have to compile kernel modules and ALSA modules separately.
86     </p>
87     <p>
88     First we'll make sure that our kernel configuration is ready for use with ALSA.
89     All you need in your kernel configuration is having Sound Card Support set to be built as a module (M).
90     This will build <c>soundcore.o</c>.
91     </p>
92     <p>
93     <note>
94     Possibly, this will also work when you built Sound Card Support in the kernel (Y) instead of building it as a module (M).
95     However, the official ALSA documentation suggests building it as a module, since ALSA will try loading it.
96     </note>
97     </p>
98     <p>If you already have a working kernel configuration, make sure you remove all sound drivers (except for Sound Card Support).
99     If you wish to do this without having to reboot, you could do like this:
100     </p>
101     <pre>
102     # <c>cd /usr/src/linux</c>
103 zhen 1.4 # <c>cp .config ~/</c>
104 drobbins 1.1 # <c>make mrproper</c>
105     # <c>cp ~/.config .</c>
106     # <c>make menuconfig</c>
107     </pre>
108     <p>
109     Now select <e>Sound Card Support</e> as Module (M) and deselect all other sound drivers.
110     Exit and say Y to save your kernel configuration.
111     After that, build the modules:
112     </p>
113     <pre>
114     # <c>make dep clean</c>
115     # <c>make modules modules_install</c>
116     </pre>
117     <p>
118     Before installing your new modules, this last line will delete all your previous modules,
119     even the ones from a previous ALSA installation.
120     </p>
121     <p>
122     <impo>
123     This means, whenever you recompile your kernel later on, you MUST recompile <c>alsa-driver</c>.
124     </impo>
125     </p>
126     <p>
127     <note>However, there's no need to reinstall <c>nvidia-kernel</c>, the Nvidia drivers are in a separate directory
128     in <path>/lib/modules/*/video</path> and won't get deleted by a <c>make modules modules_install</c>
129     </note>
130     </p>
131     </body>
132     </section>
133    
134     <section>
135     <title>ALSA modules</title>
136     <body>
137    
138     <p>
139     Now it's time to install the ALSA drivers for your soundcard(s). If your soundcard is PCI, you can find out the name
140     and type of your soundcard by looking at the output of /proc/pci
141 seo 1.5 <pre>#<c>grep audio /proc/pci</c></pre>
142 drobbins 1.1 </p>
143    
144     <p>
145     <warn>
146     If you had a previous sound setup and there are still non-ALSA sound modules loaded, unload them <e>now</e>.
147     Check with <c>lsmod</c> and use <c>rmmod</c> to unload all sound-related modules on your system.
148     </warn>
149     </p>
150    
151     <p>
152     We could simply do an <c>emerge alsa-driver</c> now, this would compile and install <e>all</e> ALSA sound drivers.
153     </p>
154     <p>
155     However, to save some time, lookup the <e>Module Name</e> of your soundcard(s) on the
156     <uri link="http://www.alsa-project.org/alsa-doc">ALSA Soundcard Matrix</uri> under the <e>Install</e> section.
157     Mine is <c>EMU10K1</c>, since I have an SBlive! soundcard.
158     We'll set ALSA_CARDS environment to this value before emerging, so emerge will only compile the drivers we need.
159     </p>
160    
161     <p>
162     <pre>
163     # <c>env ALSA_CARDS='emu10k1' emerge alsa-driver</c>
164     </pre>
165     </p>
166     <p>
167     <note>
168     When you want to install ALSA drivers for more than one soundcard, you could set ALSA_CARDS to a space-separated list
169     of drivers; like this: <c>env ALSA_CARDS='emu10k1 intel8x0 ens1370' emerge alsa-driver</c>
170     </note>
171    
172     <note>If you want to have OSS compatibility, make sure to emerge <i>alsa-oss</i>, it is the ALSA/OSS compatibility
173     wrapper. </note>
174    
175     </p>
176     <p>
177     After this, the ALSA modules should be installed on your system.
178     </p>
179     </body>
180     </section>
181     <section>
182     <title>Configuration of ALSA</title>
183     <body>
184     <p>
185     Let's start configuring now to get ALSA working properly.
186     We'll need to edit some files, to let our system know about the freshly installed ALSA modules.
187     </p>
188     <p>
189     First file to edit is <path>/etc/modules.d/alsa</path>.
190     </p>
191     <warn>
192     There is no need to edit <path>/etc/modules.conf</path>. Instead, always edit files in <path>/etc/modules.d</path>.
193     </warn>
194     <p>
195     Check the ALSA portion <e>at the top of the file</e>.
196     By adding this line you can specify the max number of soundcards you have (generally, just one).
197     </p>
198     <p>
199     <pre caption="At the top of /etc/modules.d/alsa">
200     # Alsa 0.9.X kernel modules' configuration file.
201 seo 1.5 # $Header: /home/cvsroot//gentoo-src/gentoo-xml/htdocs/doc/en/alsa-guide.xml,v 1.4 2003/01/12 19:43:05 zhen Exp $
202 drobbins 1.1
203     # ALSA portion
204     alias char-major-116 snd
205     <c>options snd snd_major=116 snd_cards_limit=1</c>
206     # OSS/Free portion
207     alias char-major-14 soundcore
208    
209     ##
210     ## IMPORTANT:
211     </pre>
212     </p>
213     <p>
214     Now we'll specify the sounddriver(s) ALSA should use. In the same file, edit like this:
215     <pre caption="A bit lower in /etc/modules.d/alsa">
216     ## and then run `update-modules' command.
217     ## Read alsa-driver's INSTALL file in /usr/share/doc for more info.
218     ##
219     ## ALSA portion
220     <c>alias snd-card-0 snd-emu10k1</c>
221     <c>## If you have more than one, add:
222     ## alias snd-card-1 snd-intel8x0
223     ## alias snd-card-2 snd-ens1370</c>
224     ## OSS/Free portion
225     ## alias sound-slot-0 snd-card-0
226     ## alias sound-slot-1 snd-card-1
227     ##
228     </pre>
229     </p>
230     <p>
231     <note>
232     If you have more than one soundcard, adjust the <c>snd_cards_limit</c> value and add more snd-card aliases to the file.
233     I don't have experience with this, but you can find examples for configurations with two or more soundcards in
234     <uri link="http://www.alsa-project.org/alsa-doc/alsa-howto/c1660.htm">Chapter 6</uri>
235     of the <uri link="http://www.alsa-project.org/alsa-doc/alsa-howto/alsa-howto.html">ALSA Howto</uri>.
236     </note>
237     </p>
238     <p>
239     Last thing to do in this file, at the very bottom, check if these lines are there and uncommented:
240     <pre caption="at the very bottom of /etc/modules.d/alsa">
241     alias /dev/mixer snd-mixer-oss
242     alias /dev/dsp snd-pcm-oss
243     alias /dev/midi snd-seq-oss
244     </pre>
245     </p>
246     <p>
247     Now double-check the file <path>/etc/modules.d/alsa</path> and when you're sure everyting is ok, run <c>update-modules</c>.
248     <pre>
249     # <c>update-modules</c>
250     </pre>
251     </p>
252     <note>
253     Running <c>update-modules</c> here will insert the data from <path>/etc/modules.d/alsa</path> into <path>/etc/modules.conf</path>
254     </note>
255     <p>
256     You should also verify that /etc/devfsd.conf has the alsa devices and permissions correctly registered.
257     </p>
258     <pre>
259     # nano -w /etc/devfsd.conf
260     </pre>
261     <pre>
262     # ALSA/OSS stuff
263     # Comment/change these if you want to change the permissions on
264     # the audio devices
265     LOOKUP snd MODLOAD ACTION snd
266     LOOKUP dsp MODLOAD
267     LOOKUP mixer MODLOAD
268     LOOKUP midi MODLOAD
269     REGISTER sound/.* PERMISSIONS root.audio 660
270     REGISTER snd/.* PERMISSIONS root.audio 660
271     </pre>
272     <note>
273     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.
274     </note>
275     </body>
276     </section>
277     </chapter>
278     <chapter>
279     <title>Starting ALSA</title>
280     <section>
281     <title>Adding alsasound to a runlevel</title>
282     <body>
283     <p>
284     First thing to do now, is to make ALSA startup at boottime. Like this:
285     <pre>
286     # <c>rc-update add alsasound boot</c>
287     </pre>
288     </p>
289     <p>
290     <warn>Note that the alsasound script should be added to the "boot" runlevel, not the "default" runlevel.</warn>
291     </p>
292     </body>
293     </section>
294     <section>
295     <title>Running and unmuting</title>
296     <body>
297     <p>
298     Since we're Linux users, we don't want to reboot. So we'll start the alsasound script manually.
299     </p>
300     <pre>
301     # <c>/etc/init.d/alsasound start</c>
302     </pre>
303     <p>
304     ALSA is running now. If everything is ok, you should be able to see the ALSA modules loaded when running <c>lsmod</c>.
305     However, sound won't work yet, because the channels are still muted. We need <c>alsa-utils</c> for this.
306     </p>
307     <pre>
308     # <c>emerge alsa-utils</c>
309     # <c>amixer</c>
310     </pre>
311     <p>
312     <warn>
313     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
314     <c>snd-mixer-oss</c> and <c>snd-pcm-oss</c> once. After that run amixer again.
315     </warn>
316     </p>
317     <pre caption="only if you get an error when running amixer">
318     # <c>insmod snd-mixer-oss</c>
319     # <c>insmod snd-pcm-oss</c>
320     # <c>amixer</c>
321     </pre>
322     <p>
323     If you got this far, now unmute both Master and PCM channels.
324     </p>
325     <p>
326     <pre>
327     # <c>amixer set Master 100 unmute</c>
328     # <c>amixer set PCM 100 unmute</c>
329     # <c>aplay /usr/kde/3/share/sounds/pop.wav</c> <codenote>(pop.wav is part of KDE)</codenote>
330     </pre>
331     </p>
332     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.
333     Then, adjust the volume settings to your liking; the ncurses-based <c>alsamixer</c> is a great way to get them "just so".
334     <p>
335     You may want to emerge <c>alsa-xmms</c> as that will provide ALSA support for XMMS.
336     </p>
337     When you reboot your system, the <e>alsasound</e> init script will properly save and restore your volume settings.
338     </body>
339     </section>
340     </chapter>
341     <chapter>
342     <title>Final Notes</title>
343     <section>
344     <title>After kernel-upgrades..</title>
345     <body>
346     <p>When you ever rebuild your kernel, or upgrade to another kernel, you'll have to rebuild the ALSA modules.</p>
347     <p>Although you might have installed <c>alsa-driver</c>, <c>alsa-libs</c> and <c>alsa-utils</c>, only the first will
348     have to be installed again, since it will put the alsa modules in
349     <path>/lib/modules/*/kernel/sound/pci/</path>.</p>
350     <pre caption="needed after each kernel compile">
351     emerge alsa-driver
352     </pre>
353     </body>
354     </section>
355     <section>
356     <title>/etc/modules.autoload</title>
357     <body>
358     <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
359     load the correct modules at startup.</p>
360     <p>It's not necessary to add <c>snd-pcm-oss</c> or <c>snd-mixer-oss</c> in this file.
361     Check the <uri link="http://www.djcj.org/LAU/guide/alsbook/faq1.html">this FAQ</uri> for more info.</p>
362     </body>
363     </section>
364     <section>
365     <title>More links..</title>
366     <body>
367     <p>
368     You could check these for additional info:
369     </p>
370     <p>
371     <ul>
372     <li><uri link="http://www.gentoo.org/doc/desktop.html">The Gentoo Linux Desktop Configuration Guide</uri></li>
373     <li><uri link="http://www.alsa-project.org">ALSA Project Homepage</uri></li>
374     <li><uri link="http://www.alsa-project.org/documentation.php3">ALSA Users Documentation</uri></li>
375     <li><uri link="http://www.djcj.org">ALSA Howto's and FAQ's</uri></li>
376     <li><uri link="http://tldp.org/HOWTO/Sound-HOWTO/index.html">Linux Sound HOWTO</uri></li>
377     <li><uri link="http://linux-sound.org/">Sound and MIDI Software For Linux</uri></li>
378     </ul>
379     </p>
380     </body>
381     </section>
382     </chapter>
383     </guide>

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