/[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 1.14 - (hide annotations) (download) (as text)
Fri Sep 12 09:40:07 2003 UTC (10 years, 10 months ago) by bennyc
Branch: MAIN
Changes since 1.13: +9 -6 lines
File MIME type: application/xml
replaced update-modules to modules-update
and <c> inside <pre> changed to <i>

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 peesh 1.10 <author title="Author"><mail link="g2boojum@gentoo.org">
10     Grant Goodyear</mail>
11     </author>
12     <author title="Author"><mail link="agenkin@gentoo.org">
13     Arcady Genkin</mail>
14     </author>
15 drobbins 1.1 <author title="Editor"><mail link="zhen@gentoo.org">
16     John P. Davis</mail>
17     </author>
18 swift 1.12 <author title="Editor"><mail link="swift@gentoo.org">
19     Sven Vermeulen</mail>
20     </author>
21 bennyc 1.14 <author title="Editor"><mail link="bennyc@gentoo.org">
22     Benny Chuang</mail>
23     </author>
24 drobbins 1.1
25 swift 1.11 <license/>
26    
27 drobbins 1.1 <abstract>
28     This guide will show you how to set up the Advanced Linux Sound Architecture (ALSA) on Gentoo Linux.
29     In addition to the Gentoo Linux Desktop Configuration Guide, this guide is supposed to give you more information on this subject. </abstract>
30    
31 bennyc 1.14 <version>1.3.1</version>
32     <date>September 12, 2003</date>
33 drobbins 1.1
34     <chapter>
35     <title>Introduction</title>
36     <section>
37     <title>What is ALSA?</title>
38     <body>
39     <p>
40     The Advanced Linux Sound Architecture (ALSA) is a project to improve the Linux sound subsystem by rewriting
41     large chunks of it.
42     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.
43     </p>
44    
45     <p>
46     ALSA provides audio and MIDI functionality for Linux.
47     </p>
48    
49     <p>
50     Quoted from <uri>http://www.alsa-project.org</uri>, ALSA has the following features:
51     <ul><li> Efficient support for all types of audio interfaces, from consumer soundcards to professional multichannel audio interfaces.</li>
52     <li> Fully modularized sound drivers.</li>
53     <li> SMP and thread-safe design.</li>
54     <li> User space library (alsa-lib) to simplify application programming and provide higher level functionality.</li>
55     <li> Support for the older OSS API, providing binary compatibility for most OSS programs.</li>
56     </ul>
57     There's lots more to ALSA however, like support for Full Duplex playback and recording, multiple soundcard support,
58     hardware mixing of streams, extensive mixer capabilities (to support advanced features of new soundcards), ...
59     </p>
60     </body>
61     </section>
62     <section>
63     <title>Why use ALSA?</title>
64     <body>
65     <p>
66     If your soundcard is supported by the Linux kernel sound system or the commercial OSS/4Front sound driver system,
67     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.
68     If you want this, just read through the <uri link="http://www.tldp.org/HOWTO/Sound-HOWTO/index.html">Linux Sound HOWTO</uri>.
69     </p>
70     <p>
71     However, those OSS/4Front drivers have some limitations -- being commercial is one.
72     ALSA is an attempt to go beyond these limitations and to do so in an open source fashion.
73     ALSA is a fully GPL and LGPL'ed sound driver system, that provides a professional quality system for recording, playback,
74     and MIDI sequencing.
75     </p>
76     </body>
77     </section>
78     <section>
79     <title>What cards does ALSA support?</title>
80     <body>
81     <p>
82     ALSA tries to support as many (new) cards as possible by providing open-source drivers.
83     However, some vendors may provide binary-only packages.
84     </p>
85     <p>To know if your card is supported, you can find a Soundcard Matrix of supported and not-supported cards here:
86     <uri>http://www.alsa-project.org/alsa-doc/</uri>.
87     </p>
88     </body>
89     </section>
90     </chapter>
91    
92     <chapter>
93     <title>Installation</title>
94     <section>
95     <title>Kernel modules</title>
96     <body>
97     <p>
98 seo 1.8 Since we're still using 2.4.x kernel sources, we'll have to compile kernel modules and ALSA modules separately. People who are using a 2.5.x kernel can do this from within their kernel configuration, since the ALSA modules are included in the kernel sources and should be built there.
99 drobbins 1.1 </p>
100     <p>
101     First we'll make sure that our kernel configuration is ready for use with ALSA.
102     All you need in your kernel configuration is having Sound Card Support set to be built as a module (M).
103     This will build <c>soundcore.o</c>.
104     </p>
105     <p>
106     <note>
107     Possibly, this will also work when you built Sound Card Support in the kernel (Y) instead of building it as a module (M).
108     However, the official ALSA documentation suggests building it as a module, since ALSA will try loading it.
109     </note>
110     </p>
111     <p>If you already have a working kernel configuration, make sure you remove all sound drivers (except for Sound Card Support).
112     If you wish to do this without having to reboot, you could do like this:
113     </p>
114     <pre>
115     # <c>cd /usr/src/linux</c>
116 zhen 1.4 # <c>cp .config ~/</c>
117 drobbins 1.1 # <c>make mrproper</c>
118     # <c>cp ~/.config .</c>
119     # <c>make menuconfig</c>
120     </pre>
121     <p>
122     Now select <e>Sound Card Support</e> as Module (M) and deselect all other sound drivers.
123     Exit and say Y to save your kernel configuration.
124     After that, build the modules:
125     </p>
126     <pre>
127     # <c>make dep clean</c>
128     # <c>make modules modules_install</c>
129     </pre>
130     <p>
131     Before installing your new modules, this last line will delete all your previous modules,
132     even the ones from a previous ALSA installation.
133     </p>
134     <p>
135     <impo>
136     This means, whenever you recompile your kernel later on, you MUST recompile <c>alsa-driver</c>.
137     </impo>
138     </p>
139     <p>
140     <note>However, there's no need to reinstall <c>nvidia-kernel</c>, the Nvidia drivers are in a separate directory
141     in <path>/lib/modules/*/video</path> and won't get deleted by a <c>make modules modules_install</c>
142     </note>
143     </p>
144     </body>
145     </section>
146    
147     <section>
148     <title>ALSA modules</title>
149     <body>
150    
151     <p>
152     Now it's time to install the ALSA drivers for your soundcard(s). If your soundcard is PCI, you can find out the name
153     and type of your soundcard by looking at the output of /proc/pci
154 seo 1.8 <pre># <c>grep audio /proc/pci</c></pre>
155 drobbins 1.1 </p>
156    
157     <p>
158     <warn>
159     If you had a previous sound setup and there are still non-ALSA sound modules loaded, unload them <e>now</e>.
160     Check with <c>lsmod</c> and use <c>rmmod</c> to unload all sound-related modules on your system.
161     </warn>
162     </p>
163    
164     <p>
165     We could simply do an <c>emerge alsa-driver</c> now, this would compile and install <e>all</e> ALSA sound drivers.
166     </p>
167     <p>
168     However, to save some time, lookup the <e>Module Name</e> of your soundcard(s) on the
169 seo 1.8 <uri link="http://www.alsa-project.org/alsa-doc">ALSA Soundcard Matrix</uri> by following the <e>Details</e> link in the <e>Driver and Docs</e> column in the row of the chipset of your soundcard.
170     Mine is <c>snd-emu10k1</c>, since I have an SBlive! soundcard, with the <e>EMU10K1</e> chipset.
171     We'll set ALSA_CARDS environment to the value of the module name before emerging (but without the snd prefix), so emerge will only compile the drivers we need.
172 drobbins 1.1 </p>
173    
174     <pre>
175     # <c>env ALSA_CARDS='emu10k1' emerge alsa-driver</c>
176     </pre>
177     <note>
178 seo 1.8 You can also add this value in <path>/etc/make.conf</path>, so when you have to emerge the alsa-driver later on you can just run <c>emerge alsa-driver</c>.
179     For example, like this: <c>echo 'ALSA_CARDS="emu10k1"' >> /etc/make.conf</c>
180     </note>
181    
182     <note>
183 drobbins 1.1 When you want to install ALSA drivers for more than one soundcard, you could set ALSA_CARDS to a space-separated list
184     of drivers; like this: <c>env ALSA_CARDS='emu10k1 intel8x0 ens1370' emerge alsa-driver</c>
185     </note>
186    
187     <note>If you want to have OSS compatibility, make sure to emerge <i>alsa-oss</i>, it is the ALSA/OSS compatibility
188     wrapper. </note>
189    
190 swift 1.13 <note>If you plan on recompiling your kernels numerous times, it might
191     be adviseable to emerge <c>alsa-driver</c> with <c>--buildpkg</c>. This
192     will create a binary package for it. Later, after recompiling your kernel,
193     you can just do <c>emerge --usepkg alsa-driver</c> which will install the
194     binary package instead of recompiling it completely.</note>
195    
196 drobbins 1.1 <p>
197     After this, the ALSA modules should be installed on your system.
198     </p>
199     </body>
200     </section>
201     <section>
202     <title>Configuration of ALSA</title>
203     <body>
204     <p>
205     Let's start configuring now to get ALSA working properly.
206     We'll need to edit some files, to let our system know about the freshly installed ALSA modules.
207     </p>
208 swift 1.12
209 drobbins 1.1 <p>
210 swift 1.12 First, install <c>alsa-utils</c> on your system:
211     </p>
212    
213     <pre caption = "Emerging alsa-utils">
214     # <i>emerge alsa-utils</i>
215     </pre>
216    
217     <p>
218     Hereafter, we need to edit <path>/etc/modules.d/alsa</path>.
219 drobbins 1.1 </p>
220     <warn>
221     There is no need to edit <path>/etc/modules.conf</path>. Instead, always edit files in <path>/etc/modules.d</path>.
222     </warn>
223     <p>
224 zhen 1.7 Check the ALSA portion <e>at the bottom of the file</e>.
225     By tweaking this line you can specify the max number of soundcards you have (generally, just one).
226 drobbins 1.1 </p>
227     <p>
228 seo 1.8 <pre caption="At the bottom of /etc/modules.d/alsa">
229     # Set this to the correct number of cards.
230     <c>options snd cards_limit=1</c>
231 drobbins 1.1 </pre>
232     </p>
233     <p>
234     Now we'll specify the sounddriver(s) ALSA should use. In the same file, edit like this:
235 seo 1.8 <pre caption="In /etc/modules.d/alsa">
236 bennyc 1.14 ## and then run `modules-update' command.
237 drobbins 1.1 ## Read alsa-driver's INSTALL file in /usr/share/doc for more info.
238     ##
239     ## ALSA portion
240     <c>alias snd-card-0 snd-emu10k1</c>
241     <c>## If you have more than one, add:
242     ## alias snd-card-1 snd-intel8x0
243     ## alias snd-card-2 snd-ens1370</c>
244     ## OSS/Free portion
245     ## alias sound-slot-0 snd-card-0
246     ## alias sound-slot-1 snd-card-1
247     ##
248     </pre>
249     </p>
250     <p>
251     <note>
252 zhen 1.6 If you have more than one soundcard, adjust the <c>cards_limit</c> value and add more snd-card aliases to the file.
253 drobbins 1.1 I don't have experience with this, but you can find examples for configurations with two or more soundcards in
254     <uri link="http://www.alsa-project.org/alsa-doc/alsa-howto/c1660.htm">Chapter 6</uri>
255     of the <uri link="http://www.alsa-project.org/alsa-doc/alsa-howto/alsa-howto.html">ALSA Howto</uri>.
256     </note>
257     </p>
258     <p>
259 seo 1.8 Last thing to do in this file, almost at the end, check if these lines are there and uncommented:
260     <pre caption="Near the end of /etc/modules.d/alsa">
261 drobbins 1.1 alias /dev/mixer snd-mixer-oss
262     alias /dev/dsp snd-pcm-oss
263     alias /dev/midi snd-seq-oss
264     </pre>
265     </p>
266     <p>
267 bennyc 1.14 Now double-check the file <path>/etc/modules.d/alsa</path> and when you're sure everyting is ok, run <c>modules-update</c>.
268 drobbins 1.1 <pre>
269 bennyc 1.14 # <i>modules-update</i>
270 drobbins 1.1 </pre>
271     </p>
272     <note>
273 bennyc 1.14 Running <c>modules-update</c> here will insert the data from <path>/etc/modules.d/alsa</path> into <path>/etc/modules.conf</path>
274 drobbins 1.1 </note>
275     <p>
276     You should also verify that /etc/devfsd.conf has the alsa devices and permissions correctly registered.
277     </p>
278 seo 1.8 <pre caption="/etc/devfsd.conf">
279 drobbins 1.1 # ALSA/OSS stuff
280     # Comment/change these if you want to change the permissions on
281     # the audio devices
282     LOOKUP snd MODLOAD ACTION snd
283     LOOKUP dsp MODLOAD
284     LOOKUP mixer MODLOAD
285     LOOKUP midi MODLOAD
286     REGISTER sound/.* PERMISSIONS root.audio 660
287     REGISTER snd/.* PERMISSIONS root.audio 660
288     </pre>
289     <note>
290     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.
291     </note>
292     </body>
293     </section>
294     </chapter>
295     <chapter>
296     <title>Starting ALSA</title>
297     <section>
298     <title>Adding alsasound to a runlevel</title>
299     <body>
300     <p>
301     First thing to do now, is to make ALSA startup at boottime. Like this:
302     <pre>
303     # <c>rc-update add alsasound boot</c>
304     </pre>
305     </p>
306     <p>
307     <warn>Note that the alsasound script should be added to the "boot" runlevel, not the "default" runlevel.</warn>
308     </p>
309     </body>
310     </section>
311     <section>
312     <title>Running and unmuting</title>
313     <body>
314     <p>
315     Since we're Linux users, we don't want to reboot. So we'll start the alsasound script manually.
316     </p>
317     <pre>
318     # <c>/etc/init.d/alsasound start</c>
319     </pre>
320     <p>
321     ALSA is running now. If everything is ok, you should be able to see the ALSA modules loaded when running <c>lsmod</c>.
322 swift 1.12 However, sound won't work yet, because the channels are still muted. We need <c>amixer</c> for this.
323 drobbins 1.1 </p>
324 swift 1.12 <pre caption = "Running amixer">
325     # <i>amixer</i>
326 drobbins 1.1 </pre>
327     <p>
328     <warn>
329     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
330     <c>snd-mixer-oss</c> and <c>snd-pcm-oss</c> once. After that run amixer again.
331     </warn>
332     </p>
333     <pre caption="only if you get an error when running amixer">
334     # <c>insmod snd-mixer-oss</c>
335     # <c>insmod snd-pcm-oss</c>
336     # <c>amixer</c>
337     </pre>
338     <p>
339 swift 1.13 If you got this far, now unmute Master and PCM channels. Some hardware
340     even requires you to unmute the center channel or even the surround
341     channel.
342 drobbins 1.1 </p>
343     <p>
344 swift 1.13 <pre caption = "Unmuting channels">
345     # <i>amixer set Master 100 unmute</i>
346     # <i>amixer set PCM 100 unmute</i>
347     <comment>Only if the above doesn't succeed on its own:</comment>
348     # <i>amixer set Center 100 unmute</i>
349     # <i>amixer set Surround 100 unmute</i>
350     <comment>Test the sound:</comment>
351     # <i>aplay $KDEDIR/share/sounds/pop.wav</i> <codenote>(pop.wav is part of KDE)</codenote>
352 drobbins 1.1 </pre>
353     </p>
354     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.
355     Then, adjust the volume settings to your liking; the ncurses-based <c>alsamixer</c> is a great way to get them "just so".
356     <p>
357     You may want to emerge <c>alsa-xmms</c> as that will provide ALSA support for XMMS.
358     </p>
359     When you reboot your system, the <e>alsasound</e> init script will properly save and restore your volume settings.
360     </body>
361     </section>
362     </chapter>
363     <chapter>
364     <title>Final Notes</title>
365     <section>
366     <title>After kernel-upgrades..</title>
367     <body>
368     <p>When you ever rebuild your kernel, or upgrade to another kernel, you'll have to rebuild the ALSA modules.</p>
369     <p>Although you might have installed <c>alsa-driver</c>, <c>alsa-libs</c> and <c>alsa-utils</c>, only the first will
370     have to be installed again, since it will put the alsa modules in
371     <path>/lib/modules/*/kernel/sound/pci/</path>.</p>
372     <pre caption="needed after each kernel compile">
373 seo 1.8 # <c>emerge alsa-driver</c>
374 drobbins 1.1 </pre>
375     </body>
376     </section>
377     <section>
378     <title>/etc/modules.autoload</title>
379     <body>
380     <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
381     load the correct modules at startup.</p>
382     <p>It's not necessary to add <c>snd-pcm-oss</c> or <c>snd-mixer-oss</c> in this file.
383     Check the <uri link="http://www.djcj.org/LAU/guide/alsbook/faq1.html">this FAQ</uri> for more info.</p>
384     </body>
385     </section>
386     <section>
387     <title>More links..</title>
388     <body>
389     <p>
390     You could check these for additional info:
391     </p>
392     <p>
393     <ul>
394 seo 1.8 <li><uri link="http://www.gentoo.org/doc/en/desktop.xml">The Gentoo Linux Desktop Configuration Guide</uri></li>
395 drobbins 1.1 <li><uri link="http://www.alsa-project.org">ALSA Project Homepage</uri></li>
396     <li><uri link="http://www.alsa-project.org/documentation.php3">ALSA Users Documentation</uri></li>
397     <li><uri link="http://www.djcj.org">ALSA Howto's and FAQ's</uri></li>
398     <li><uri link="http://tldp.org/HOWTO/Sound-HOWTO/index.html">Linux Sound HOWTO</uri></li>
399     <li><uri link="http://linux-sound.org/">Sound and MIDI Software For Linux</uri></li>
400     </ul>
401     </p>
402     </body>
403     </section>
404     </chapter>
405     </guide>

  ViewVC Help
Powered by ViewVC 1.1.20