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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 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 blubber 1.16 <author title="Editor"><mail link="blubber@gentoo.org">
25     Tiemo Kieft</mail>
26     </author>
27 drobbins 1.1
28 swift 1.11 <license/>
29    
30 drobbins 1.1 <abstract>
31     This guide will show you how to set up the Advanced Linux Sound Architecture (ALSA) on Gentoo Linux.
32     In addition to the Gentoo Linux Desktop Configuration Guide, this guide is supposed to give you more information on this subject. </abstract>
33    
34 blubber 1.16 <version>1.3.2</version>
35     <date>September 25, 2003</date>
36 drobbins 1.1
37     <chapter>
38     <title>Introduction</title>
39     <section>
40     <title>What is ALSA?</title>
41     <body>
42     <p>
43     The Advanced Linux Sound Architecture (ALSA) is a project to improve the Linux sound subsystem by rewriting
44     large chunks of it.
45     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.
46     </p>
47    
48     <p>
49     ALSA provides audio and MIDI functionality for Linux.
50     </p>
51    
52     <p>
53     Quoted from <uri>http://www.alsa-project.org</uri>, ALSA has the following features:
54     <ul><li> Efficient support for all types of audio interfaces, from consumer soundcards to professional multichannel audio interfaces.</li>
55     <li> Fully modularized sound drivers.</li>
56     <li> SMP and thread-safe design.</li>
57     <li> User space library (alsa-lib) to simplify application programming and provide higher level functionality.</li>
58     <li> Support for the older OSS API, providing binary compatibility for most OSS programs.</li>
59     </ul>
60     There's lots more to ALSA however, like support for Full Duplex playback and recording, multiple soundcard support,
61     hardware mixing of streams, extensive mixer capabilities (to support advanced features of new soundcards), ...
62     </p>
63     </body>
64     </section>
65     <section>
66     <title>Why use ALSA?</title>
67     <body>
68     <p>
69     If your soundcard is supported by the Linux kernel sound system or the commercial OSS/4Front sound driver system,
70     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.
71     If you want this, just read through the <uri link="http://www.tldp.org/HOWTO/Sound-HOWTO/index.html">Linux Sound HOWTO</uri>.
72     </p>
73     <p>
74     However, those OSS/4Front drivers have some limitations -- being commercial is one.
75     ALSA is an attempt to go beyond these limitations and to do so in an open source fashion.
76     ALSA is a fully GPL and LGPL'ed sound driver system, that provides a professional quality system for recording, playback,
77     and MIDI sequencing.
78     </p>
79     </body>
80     </section>
81     <section>
82     <title>What cards does ALSA support?</title>
83     <body>
84     <p>
85     ALSA tries to support as many (new) cards as possible by providing open-source drivers.
86     However, some vendors may provide binary-only packages.
87     </p>
88     <p>To know if your card is supported, you can find a Soundcard Matrix of supported and not-supported cards here:
89     <uri>http://www.alsa-project.org/alsa-doc/</uri>.
90     </p>
91     </body>
92     </section>
93     </chapter>
94    
95     <chapter>
96     <title>Installation</title>
97     <section>
98     <title>Kernel modules</title>
99     <body>
100     <p>
101 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.
102 drobbins 1.1 </p>
103     <p>
104     First we'll make sure that our kernel configuration is ready for use with ALSA.
105     All you need in your kernel configuration is having Sound Card Support set to be built as a module (M).
106     This will build <c>soundcore.o</c>.
107     </p>
108     <p>
109     <note>
110     Possibly, this will also work when you built Sound Card Support in the kernel (Y) instead of building it as a module (M).
111     However, the official ALSA documentation suggests building it as a module, since ALSA will try loading it.
112     </note>
113     </p>
114     <p>If you already have a working kernel configuration, make sure you remove all sound drivers (except for Sound Card Support).
115     If you wish to do this without having to reboot, you could do like this:
116     </p>
117     <pre>
118 blubber 1.16 # <i>cd /usr/src/linux</i>
119     # <i>cp .config ~/</i>
120     # <i>make mrproper</i>
121     # <i>cp ~/.config .</i>
122     # <i>make menuconfig</i>
123 drobbins 1.1 </pre>
124     <p>
125     Now select <e>Sound Card Support</e> as Module (M) and deselect all other sound drivers.
126     Exit and say Y to save your kernel configuration.
127     After that, build the modules:
128     </p>
129     <pre>
130 blubber 1.16 # <i>make dep clean</i>
131     # <i>make modules modules_install</i>
132 drobbins 1.1 </pre>
133     <p>
134     Before installing your new modules, this last line will delete all your previous modules,
135     even the ones from a previous ALSA installation.
136     </p>
137     <p>
138     <impo>
139     This means, whenever you recompile your kernel later on, you MUST recompile <c>alsa-driver</c>.
140     </impo>
141     </p>
142     <p>
143     <note>However, there's no need to reinstall <c>nvidia-kernel</c>, the Nvidia drivers are in a separate directory
144     in <path>/lib/modules/*/video</path> and won't get deleted by a <c>make modules modules_install</c>
145     </note>
146     </p>
147     </body>
148     </section>
149    
150     <section>
151     <title>ALSA modules</title>
152     <body>
153    
154     <p>
155     Now it's time to install the ALSA drivers for your soundcard(s). If your soundcard is PCI, you can find out the name
156 blubber 1.16 and type of your soundcard by looking at the output of /proc/pci.
157 drobbins 1.1 </p>
158 blubber 1.16 <pre>
159     # <i>grep audio /proc/pci</i>
160     </pre>
161    
162 drobbins 1.1
163     <p>
164     <warn>
165     If you had a previous sound setup and there are still non-ALSA sound modules loaded, unload them <e>now</e>.
166     Check with <c>lsmod</c> and use <c>rmmod</c> to unload all sound-related modules on your system.
167     </warn>
168     </p>
169    
170     <p>
171     We could simply do an <c>emerge alsa-driver</c> now, this would compile and install <e>all</e> ALSA sound drivers.
172     </p>
173     <p>
174     However, to save some time, lookup the <e>Module Name</e> of your soundcard(s) on the
175 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.
176     Mine is <c>snd-emu10k1</c>, since I have an SBlive! soundcard, with the <e>EMU10K1</e> chipset.
177     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.
178 drobbins 1.1 </p>
179    
180     <pre>
181 blubber 1.16 # <i>env ALSA_CARDS='emu10k1' emerge alsa-driver</i>
182 drobbins 1.1 </pre>
183     <note>
184 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>.
185     For example, like this: <c>echo 'ALSA_CARDS="emu10k1"' >> /etc/make.conf</c>
186     </note>
187    
188     <note>
189 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
190     of drivers; like this: <c>env ALSA_CARDS='emu10k1 intel8x0 ens1370' emerge alsa-driver</c>
191     </note>
192    
193     <note>If you want to have OSS compatibility, make sure to emerge <i>alsa-oss</i>, it is the ALSA/OSS compatibility
194     wrapper. </note>
195    
196 swift 1.13 <note>If you plan on recompiling your kernels numerous times, it might
197     be adviseable to emerge <c>alsa-driver</c> with <c>--buildpkg</c>. This
198     will create a binary package for it. Later, after recompiling your kernel,
199     you can just do <c>emerge --usepkg alsa-driver</c> which will install the
200     binary package instead of recompiling it completely.</note>
201    
202 drobbins 1.1 <p>
203     After this, the ALSA modules should be installed on your system.
204     </p>
205     </body>
206     </section>
207     <section>
208     <title>Configuration of ALSA</title>
209     <body>
210     <p>
211     Let's start configuring now to get ALSA working properly.
212     We'll need to edit some files, to let our system know about the freshly installed ALSA modules.
213     </p>
214 swift 1.12
215 drobbins 1.1 <p>
216 swift 1.12 First, install <c>alsa-utils</c> on your system:
217     </p>
218    
219     <pre caption = "Emerging alsa-utils">
220     # <i>emerge alsa-utils</i>
221     </pre>
222    
223     <p>
224     Hereafter, we need to edit <path>/etc/modules.d/alsa</path>.
225 drobbins 1.1 </p>
226     <warn>
227     There is no need to edit <path>/etc/modules.conf</path>. Instead, always edit files in <path>/etc/modules.d</path>.
228     </warn>
229     <p>
230 zhen 1.7 Check the ALSA portion <e>at the bottom of the file</e>.
231     By tweaking this line you can specify the max number of soundcards you have (generally, just one).
232 drobbins 1.1 </p>
233 seo 1.8 <pre caption="At the bottom of /etc/modules.d/alsa">
234 blubber 1.16 <comment>Set this to the correct number of cards.</comment>
235     options snd cards_limit=1
236 drobbins 1.1 </pre>
237     <p>
238     Now we'll specify the sounddriver(s) ALSA should use. In the same file, edit like this:
239 blubber 1.16 </p>
240 seo 1.8 <pre caption="In /etc/modules.d/alsa">
241 bennyc 1.14 ## and then run `modules-update' command.
242 drobbins 1.1 ## Read alsa-driver's INSTALL file in /usr/share/doc for more info.
243     ##
244     ## ALSA portion
245 blubber 1.16 alias snd-card-0 snd-emu10k1
246     <comment>## If you have more than one, add:</comment>
247 drobbins 1.1 ## alias snd-card-1 snd-intel8x0
248 blubber 1.16 ## alias snd-card-2 snd-ens1370
249 drobbins 1.1 ## OSS/Free portion
250     ## alias sound-slot-0 snd-card-0
251     ## alias sound-slot-1 snd-card-1
252     ##
253     </pre>
254     <note>
255 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.
256 drobbins 1.1 I don't have experience with this, but you can find examples for configurations with two or more soundcards in
257     <uri link="http://www.alsa-project.org/alsa-doc/alsa-howto/c1660.htm">Chapter 6</uri>
258     of the <uri link="http://www.alsa-project.org/alsa-doc/alsa-howto/alsa-howto.html">ALSA Howto</uri>.
259     </note>
260     <p>
261 seo 1.8 Last thing to do in this file, almost at the end, check if these lines are there and uncommented:
262 blubber 1.16 </p>
263 seo 1.8 <pre caption="Near the end of /etc/modules.d/alsa">
264 drobbins 1.1 alias /dev/mixer snd-mixer-oss
265     alias /dev/dsp snd-pcm-oss
266     alias /dev/midi snd-seq-oss
267     </pre>
268     <p>
269 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>.
270 drobbins 1.1 <pre>
271 bennyc 1.14 # <i>modules-update</i>
272 drobbins 1.1 </pre>
273     </p>
274     <note>
275 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>
276 drobbins 1.1 </note>
277     <p>
278     You should also verify that /etc/devfsd.conf has the alsa devices and permissions correctly registered.
279     </p>
280 seo 1.8 <pre caption="/etc/devfsd.conf">
281 drobbins 1.1 # ALSA/OSS stuff
282     # Comment/change these if you want to change the permissions on
283     # the audio devices
284     LOOKUP snd MODLOAD ACTION snd
285     LOOKUP dsp MODLOAD
286     LOOKUP mixer MODLOAD
287     LOOKUP midi MODLOAD
288     REGISTER sound/.* PERMISSIONS root.audio 660
289     REGISTER snd/.* PERMISSIONS root.audio 660
290     </pre>
291     <note>
292     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.
293     </note>
294     </body>
295     </section>
296     </chapter>
297     <chapter>
298     <title>Starting ALSA</title>
299     <section>
300     <title>Adding alsasound to a runlevel</title>
301     <body>
302     <p>
303     First thing to do now, is to make ALSA startup at boottime. Like this:
304     <pre>
305 blubber 1.16 # <i>rc-update add alsasound boot</i>
306 drobbins 1.1 </pre>
307     </p>
308     <p>
309     <warn>Note that the alsasound script should be added to the "boot" runlevel, not the "default" runlevel.</warn>
310     </p>
311     </body>
312     </section>
313     <section>
314     <title>Running and unmuting</title>
315     <body>
316     <p>
317     Since we're Linux users, we don't want to reboot. So we'll start the alsasound script manually.
318     </p>
319     <pre>
320 blubber 1.16 # <i>/etc/init.d/alsasound start</i>
321 drobbins 1.1 </pre>
322     <p>
323     ALSA is running now. If everything is ok, you should be able to see the ALSA modules loaded when running <c>lsmod</c>.
324 swift 1.12 However, sound won't work yet, because the channels are still muted. We need <c>amixer</c> for this.
325 drobbins 1.1 </p>
326 swift 1.12 <pre caption = "Running amixer">
327     # <i>amixer</i>
328 drobbins 1.1 </pre>
329     <p>
330     <warn>
331 bennyc 1.15 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 modprobe
332 drobbins 1.1 <c>snd-mixer-oss</c> and <c>snd-pcm-oss</c> once. After that run amixer again.
333     </warn>
334     </p>
335     <pre caption="only if you get an error when running amixer">
336 bennyc 1.15 # <i>modprobe snd-mixer-oss</i>
337     # <i>modprobe snd-pcm-oss</i>
338     # <i>amixer</i>
339 drobbins 1.1 </pre>
340     <p>
341 swift 1.13 If you got this far, now unmute Master and PCM channels. Some hardware
342     even requires you to unmute the center channel or even the surround
343     channel.
344 drobbins 1.1 </p>
345     <p>
346 swift 1.13 <pre caption = "Unmuting channels">
347     # <i>amixer set Master 100 unmute</i>
348     # <i>amixer set PCM 100 unmute</i>
349     <comment>Only if the above doesn't succeed on its own:</comment>
350     # <i>amixer set Center 100 unmute</i>
351     # <i>amixer set Surround 100 unmute</i>
352     <comment>Test the sound:</comment>
353     # <i>aplay $KDEDIR/share/sounds/pop.wav</i> <codenote>(pop.wav is part of KDE)</codenote>
354 drobbins 1.1 </pre>
355     </p>
356     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.
357     Then, adjust the volume settings to your liking; the ncurses-based <c>alsamixer</c> is a great way to get them "just so".
358     <p>
359     You may want to emerge <c>alsa-xmms</c> as that will provide ALSA support for XMMS.
360     </p>
361     When you reboot your system, the <e>alsasound</e> init script will properly save and restore your volume settings.
362     </body>
363     </section>
364     </chapter>
365     <chapter>
366     <title>Final Notes</title>
367     <section>
368     <title>After kernel-upgrades..</title>
369     <body>
370     <p>When you ever rebuild your kernel, or upgrade to another kernel, you'll have to rebuild the ALSA modules.</p>
371     <p>Although you might have installed <c>alsa-driver</c>, <c>alsa-libs</c> and <c>alsa-utils</c>, only the first will
372     have to be installed again, since it will put the alsa modules in
373     <path>/lib/modules/*/kernel/sound/pci/</path>.</p>
374     <pre caption="needed after each kernel compile">
375 blubber 1.16 # <i>emerge alsa-driver</i>
376 drobbins 1.1 </pre>
377     </body>
378     </section>
379     <section>
380     <title>/etc/modules.autoload</title>
381     <body>
382     <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
383     load the correct modules at startup.</p>
384     <p>It's not necessary to add <c>snd-pcm-oss</c> or <c>snd-mixer-oss</c> in this file.
385     Check the <uri link="http://www.djcj.org/LAU/guide/alsbook/faq1.html">this FAQ</uri> for more info.</p>
386     </body>
387     </section>
388     <section>
389     <title>More links..</title>
390     <body>
391     <p>
392     You could check these for additional info:
393     </p>
394     <p>
395     <ul>
396 seo 1.8 <li><uri link="http://www.gentoo.org/doc/en/desktop.xml">The Gentoo Linux Desktop Configuration Guide</uri></li>
397 drobbins 1.1 <li><uri link="http://www.alsa-project.org">ALSA Project Homepage</uri></li>
398     <li><uri link="http://www.alsa-project.org/documentation.php3">ALSA Users Documentation</uri></li>
399     <li><uri link="http://www.djcj.org">ALSA Howto's and FAQ's</uri></li>
400     <li><uri link="http://tldp.org/HOWTO/Sound-HOWTO/index.html">Linux Sound HOWTO</uri></li>
401     <li><uri link="http://linux-sound.org/">Sound and MIDI Software For Linux</uri></li>
402     </ul>
403     </p>
404     </body>
405     </section>
406     </chapter>
407     </guide>

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