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1 zhen 1.3 <?xml version='1.0' encoding="UTF-8"?>
2 neysx 1.19 <!-- $Header$ -->
3 drobbins 1.1 <!DOCTYPE guide SYSTEM "/dtd/guide.dtd">
4    
5 zhen 1.2 <guide link = "/doc/en/alsa-guide.xml">
6 drobbins 1.1 <title>Gentoo Linux ALSA Guide</title>
7     <author title="Author"><mail link="zu@pandora.be">
8     Vincent Verleye</mail>
9     </author>
10 peesh 1.10 <author title="Author"><mail link="g2boojum@gentoo.org">
11     Grant Goodyear</mail>
12     </author>
13     <author title="Author"><mail link="agenkin@gentoo.org">
14     Arcady Genkin</mail>
15     </author>
16 swift 1.18 <author title="Editor"><!-- zhen@gentoo.org -->
17     John P. Davis
18 drobbins 1.1 </author>
19 swift 1.12 <author title="Editor"><mail link="swift@gentoo.org">
20     Sven Vermeulen</mail>
21     </author>
22 bennyc 1.14 <author title="Editor"><mail link="bennyc@gentoo.org">
23     Benny Chuang</mail>
24     </author>
25 blubber 1.16 <author title="Editor"><mail link="blubber@gentoo.org">
26     Tiemo Kieft</mail>
27     </author>
28 drobbins 1.1
29 swift 1.11 <license/>
30    
31 drobbins 1.1 <abstract>
32     This guide will show you how to set up the Advanced Linux Sound Architecture (ALSA) on Gentoo Linux.
33     In addition to the Gentoo Linux Desktop Configuration Guide, this guide is supposed to give you more information on this subject. </abstract>
34    
35 swift 1.17 <version>1.3.3</version>
36     <date>October 9, 2003</date>
37 drobbins 1.1
38     <chapter>
39     <title>Introduction</title>
40     <section>
41     <title>What is ALSA?</title>
42     <body>
43     <p>
44     The Advanced Linux Sound Architecture (ALSA) is a project to improve the Linux sound subsystem by rewriting
45     large chunks of it.
46     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.
47     </p>
48    
49     <p>
50     ALSA provides audio and MIDI functionality for Linux.
51     </p>
52    
53     <p>
54     Quoted from <uri>http://www.alsa-project.org</uri>, ALSA has the following features:
55     <ul><li> Efficient support for all types of audio interfaces, from consumer soundcards to professional multichannel audio interfaces.</li>
56     <li> Fully modularized sound drivers.</li>
57     <li> SMP and thread-safe design.</li>
58     <li> User space library (alsa-lib) to simplify application programming and provide higher level functionality.</li>
59     <li> Support for the older OSS API, providing binary compatibility for most OSS programs.</li>
60     </ul>
61     There's lots more to ALSA however, like support for Full Duplex playback and recording, multiple soundcard support,
62     hardware mixing of streams, extensive mixer capabilities (to support advanced features of new soundcards), ...
63     </p>
64     </body>
65     </section>
66     <section>
67     <title>Why use ALSA?</title>
68     <body>
69     <p>
70     If your soundcard is supported by the Linux kernel sound system or the commercial OSS/4Front sound driver system,
71     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.
72     If you want this, just read through the <uri link="http://www.tldp.org/HOWTO/Sound-HOWTO/index.html">Linux Sound HOWTO</uri>.
73     </p>
74     <p>
75     However, those OSS/4Front drivers have some limitations -- being commercial is one.
76     ALSA is an attempt to go beyond these limitations and to do so in an open source fashion.
77     ALSA is a fully GPL and LGPL'ed sound driver system, that provides a professional quality system for recording, playback,
78     and MIDI sequencing.
79     </p>
80     </body>
81     </section>
82     <section>
83     <title>What cards does ALSA support?</title>
84     <body>
85     <p>
86     ALSA tries to support as many (new) cards as possible by providing open-source drivers.
87     However, some vendors may provide binary-only packages.
88     </p>
89     <p>To know if your card is supported, you can find a Soundcard Matrix of supported and not-supported cards here:
90     <uri>http://www.alsa-project.org/alsa-doc/</uri>.
91     </p>
92     </body>
93     </section>
94     </chapter>
95    
96     <chapter>
97     <title>Installation</title>
98     <section>
99 swift 1.17 <title>Gentoo USE flags</title>
100     <body>
101    
102     <p>
103     To compile programs with ALSA-support, be sure to add <e>alsa</e> to
104     your USE-variable. However, several tools don't support alsa yet, and
105     require OSS. ALSA provides OSS-emulation if you define <e>oss</e> in your
106     USE-variable before you start.
107     </p>
108    
109     </body>
110     </section>
111    
112     <section>
113 drobbins 1.1 <title>Kernel modules</title>
114     <body>
115     <p>
116 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.
117 drobbins 1.1 </p>
118     <p>
119     First we'll make sure that our kernel configuration is ready for use with ALSA.
120     All you need in your kernel configuration is having Sound Card Support set to be built as a module (M).
121     This will build <c>soundcore.o</c>.
122     </p>
123     <p>
124     <note>
125     Possibly, this will also work when you built Sound Card Support in the kernel (Y) instead of building it as a module (M).
126     However, the official ALSA documentation suggests building it as a module, since ALSA will try loading it.
127     </note>
128     </p>
129     <p>If you already have a working kernel configuration, make sure you remove all sound drivers (except for Sound Card Support).
130     If you wish to do this without having to reboot, you could do like this:
131     </p>
132     <pre>
133 blubber 1.16 # <i>cd /usr/src/linux</i>
134     # <i>cp .config ~/</i>
135     # <i>make mrproper</i>
136     # <i>cp ~/.config .</i>
137     # <i>make menuconfig</i>
138 drobbins 1.1 </pre>
139     <p>
140     Now select <e>Sound Card Support</e> as Module (M) and deselect all other sound drivers.
141     Exit and say Y to save your kernel configuration.
142     After that, build the modules:
143     </p>
144     <pre>
145 blubber 1.16 # <i>make dep clean</i>
146     # <i>make modules modules_install</i>
147 drobbins 1.1 </pre>
148     <p>
149     Before installing your new modules, this last line will delete all your previous modules,
150     even the ones from a previous ALSA installation.
151     </p>
152     <p>
153     <impo>
154     This means, whenever you recompile your kernel later on, you MUST recompile <c>alsa-driver</c>.
155     </impo>
156     </p>
157     </body>
158     </section>
159    
160     <section>
161     <title>ALSA modules</title>
162     <body>
163    
164     <p>
165     Now it's time to install the ALSA drivers for your soundcard(s). If your soundcard is PCI, you can find out the name
166 blubber 1.16 and type of your soundcard by looking at the output of /proc/pci.
167 drobbins 1.1 </p>
168 blubber 1.16 <pre>
169     # <i>grep audio /proc/pci</i>
170     </pre>
171    
172 drobbins 1.1
173     <p>
174     <warn>
175     If you had a previous sound setup and there are still non-ALSA sound modules loaded, unload them <e>now</e>.
176     Check with <c>lsmod</c> and use <c>rmmod</c> to unload all sound-related modules on your system.
177     </warn>
178     </p>
179    
180     <p>
181     We could simply do an <c>emerge alsa-driver</c> now, this would compile and install <e>all</e> ALSA sound drivers.
182     </p>
183     <p>
184     However, to save some time, lookup the <e>Module Name</e> of your soundcard(s) on the
185 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.
186     Mine is <c>snd-emu10k1</c>, since I have an SBlive! soundcard, with the <e>EMU10K1</e> chipset.
187     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.
188 drobbins 1.1 </p>
189    
190     <pre>
191 blubber 1.16 # <i>env ALSA_CARDS='emu10k1' emerge alsa-driver</i>
192 drobbins 1.1 </pre>
193     <note>
194 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>.
195     For example, like this: <c>echo 'ALSA_CARDS="emu10k1"' >> /etc/make.conf</c>
196     </note>
197    
198     <note>
199 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
200     of drivers; like this: <c>env ALSA_CARDS='emu10k1 intel8x0 ens1370' emerge alsa-driver</c>
201     </note>
202    
203     <note>If you want to have OSS compatibility, make sure to emerge <i>alsa-oss</i>, it is the ALSA/OSS compatibility
204     wrapper. </note>
205    
206 swift 1.13 <note>If you plan on recompiling your kernels numerous times, it might
207     be adviseable to emerge <c>alsa-driver</c> with <c>--buildpkg</c>. This
208     will create a binary package for it. Later, after recompiling your kernel,
209     you can just do <c>emerge --usepkg alsa-driver</c> which will install the
210     binary package instead of recompiling it completely.</note>
211    
212 drobbins 1.1 <p>
213     After this, the ALSA modules should be installed on your system.
214     </p>
215     </body>
216     </section>
217     <section>
218     <title>Configuration of ALSA</title>
219     <body>
220     <p>
221     Let's start configuring now to get ALSA working properly.
222     We'll need to edit some files, to let our system know about the freshly installed ALSA modules.
223     </p>
224 swift 1.12
225 drobbins 1.1 <p>
226 swift 1.12 First, install <c>alsa-utils</c> on your system:
227     </p>
228    
229     <pre caption = "Emerging alsa-utils">
230     # <i>emerge alsa-utils</i>
231     </pre>
232    
233     <p>
234     Hereafter, we need to edit <path>/etc/modules.d/alsa</path>.
235 drobbins 1.1 </p>
236     <warn>
237     There is no need to edit <path>/etc/modules.conf</path>. Instead, always edit files in <path>/etc/modules.d</path>.
238     </warn>
239     <p>
240 zhen 1.7 Check the ALSA portion <e>at the bottom of the file</e>.
241     By tweaking this line you can specify the max number of soundcards you have (generally, just one).
242 drobbins 1.1 </p>
243 seo 1.8 <pre caption="At the bottom of /etc/modules.d/alsa">
244 blubber 1.16 <comment>Set this to the correct number of cards.</comment>
245     options snd cards_limit=1
246 drobbins 1.1 </pre>
247     <p>
248     Now we'll specify the sounddriver(s) ALSA should use. In the same file, edit like this:
249 blubber 1.16 </p>
250 seo 1.8 <pre caption="In /etc/modules.d/alsa">
251 bennyc 1.14 ## and then run `modules-update' command.
252 drobbins 1.1 ## Read alsa-driver's INSTALL file in /usr/share/doc for more info.
253     ##
254     ## ALSA portion
255 blubber 1.16 alias snd-card-0 snd-emu10k1
256     <comment>## If you have more than one, add:</comment>
257 drobbins 1.1 ## alias snd-card-1 snd-intel8x0
258 blubber 1.16 ## alias snd-card-2 snd-ens1370
259 drobbins 1.1 ## OSS/Free portion
260     ## alias sound-slot-0 snd-card-0
261     ## alias sound-slot-1 snd-card-1
262     ##
263     </pre>
264     <note>
265 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.
266 drobbins 1.1 I don't have experience with this, but you can find examples for configurations with two or more soundcards in
267     <uri link="http://www.alsa-project.org/alsa-doc/alsa-howto/c1660.htm">Chapter 6</uri>
268     of the <uri link="http://www.alsa-project.org/alsa-doc/alsa-howto/alsa-howto.html">ALSA Howto</uri>.
269     </note>
270     <p>
271 seo 1.8 Last thing to do in this file, almost at the end, check if these lines are there and uncommented:
272 blubber 1.16 </p>
273 seo 1.8 <pre caption="Near the end of /etc/modules.d/alsa">
274 drobbins 1.1 alias /dev/mixer snd-mixer-oss
275     alias /dev/dsp snd-pcm-oss
276     alias /dev/midi snd-seq-oss
277     </pre>
278     <p>
279 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>.
280 drobbins 1.1 <pre>
281 bennyc 1.14 # <i>modules-update</i>
282 drobbins 1.1 </pre>
283     </p>
284     <note>
285 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>
286 drobbins 1.1 </note>
287     <p>
288     You should also verify that /etc/devfsd.conf has the alsa devices and permissions correctly registered.
289     </p>
290 seo 1.8 <pre caption="/etc/devfsd.conf">
291 drobbins 1.1 # ALSA/OSS stuff
292     # Comment/change these if you want to change the permissions on
293     # the audio devices
294     LOOKUP snd MODLOAD ACTION snd
295     LOOKUP dsp MODLOAD
296     LOOKUP mixer MODLOAD
297     LOOKUP midi MODLOAD
298     REGISTER sound/.* PERMISSIONS root.audio 660
299     REGISTER snd/.* PERMISSIONS root.audio 660
300     </pre>
301     <note>
302     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.
303     </note>
304     </body>
305     </section>
306     </chapter>
307     <chapter>
308     <title>Starting ALSA</title>
309     <section>
310     <title>Adding alsasound to a runlevel</title>
311     <body>
312     <p>
313     First thing to do now, is to make ALSA startup at boottime. Like this:
314     <pre>
315 blubber 1.16 # <i>rc-update add alsasound boot</i>
316 drobbins 1.1 </pre>
317     </p>
318     <p>
319     <warn>Note that the alsasound script should be added to the "boot" runlevel, not the "default" runlevel.</warn>
320     </p>
321     </body>
322     </section>
323     <section>
324     <title>Running and unmuting</title>
325     <body>
326     <p>
327     Since we're Linux users, we don't want to reboot. So we'll start the alsasound script manually.
328     </p>
329     <pre>
330 blubber 1.16 # <i>/etc/init.d/alsasound start</i>
331 drobbins 1.1 </pre>
332     <p>
333     ALSA is running now. If everything is ok, you should be able to see the ALSA modules loaded when running <c>lsmod</c>.
334 swift 1.12 However, sound won't work yet, because the channels are still muted. We need <c>amixer</c> for this.
335 drobbins 1.1 </p>
336 swift 1.12 <pre caption = "Running amixer">
337     # <i>amixer</i>
338 drobbins 1.1 </pre>
339     <p>
340     <warn>
341 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
342 drobbins 1.1 <c>snd-mixer-oss</c> and <c>snd-pcm-oss</c> once. After that run amixer again.
343     </warn>
344     </p>
345     <pre caption="only if you get an error when running amixer">
346 bennyc 1.15 # <i>modprobe snd-mixer-oss</i>
347     # <i>modprobe snd-pcm-oss</i>
348     # <i>amixer</i>
349 drobbins 1.1 </pre>
350     <p>
351 swift 1.13 If you got this far, now unmute Master and PCM channels. Some hardware
352     even requires you to unmute the center channel or even the surround
353     channel.
354 drobbins 1.1 </p>
355     <p>
356 swift 1.13 <pre caption = "Unmuting channels">
357     # <i>amixer set Master 100 unmute</i>
358     # <i>amixer set PCM 100 unmute</i>
359     <comment>Only if the above doesn't succeed on its own:</comment>
360     # <i>amixer set Center 100 unmute</i>
361     # <i>amixer set Surround 100 unmute</i>
362     <comment>Test the sound:</comment>
363     # <i>aplay $KDEDIR/share/sounds/pop.wav</i> <codenote>(pop.wav is part of KDE)</codenote>
364 drobbins 1.1 </pre>
365     </p>
366     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.
367     Then, adjust the volume settings to your liking; the ncurses-based <c>alsamixer</c> is a great way to get them "just so".
368     <p>
369     You may want to emerge <c>alsa-xmms</c> as that will provide ALSA support for XMMS.
370     </p>
371     When you reboot your system, the <e>alsasound</e> init script will properly save and restore your volume settings.
372     </body>
373     </section>
374     </chapter>
375     <chapter>
376     <title>Final Notes</title>
377     <section>
378     <title>After kernel-upgrades..</title>
379     <body>
380     <p>When you ever rebuild your kernel, or upgrade to another kernel, you'll have to rebuild the ALSA modules.</p>
381     <p>Although you might have installed <c>alsa-driver</c>, <c>alsa-libs</c> and <c>alsa-utils</c>, only the first will
382     have to be installed again, since it will put the alsa modules in
383     <path>/lib/modules/*/kernel/sound/pci/</path>.</p>
384     <pre caption="needed after each kernel compile">
385 blubber 1.16 # <i>emerge alsa-driver</i>
386 drobbins 1.1 </pre>
387     </body>
388     </section>
389     <section>
390     <title>/etc/modules.autoload</title>
391     <body>
392     <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
393     load the correct modules at startup.</p>
394     <p>It's not necessary to add <c>snd-pcm-oss</c> or <c>snd-mixer-oss</c> in this file.
395     Check the <uri link="http://www.djcj.org/LAU/guide/alsbook/faq1.html">this FAQ</uri> for more info.</p>
396     </body>
397     </section>
398 swift 1.17
399     <section>
400     <title>Known bugs</title>
401     <body>
402    
403     <note>
404     This guide lags behind on the alsa-development. Chances are these bugs
405     are already fixed when you read this.
406     </note>
407    
408     <ul>
409     <li>
410     If you have <b>lots of noise</b> when using <b>oss</b> emulation, add
411     <e>options snd-pcm-oss dsp_map=1</e> to
412     <path>/etc/modules.d/alsa</path>.
413     </li>
414     </ul>
415    
416     </body>
417     </section>
418    
419 drobbins 1.1 <section>
420     <title>More links..</title>
421     <body>
422     <p>
423     You could check these for additional info:
424     </p>
425     <p>
426     <ul>
427 seo 1.8 <li><uri link="http://www.gentoo.org/doc/en/desktop.xml">The Gentoo Linux Desktop Configuration Guide</uri></li>
428 drobbins 1.1 <li><uri link="http://www.alsa-project.org">ALSA Project Homepage</uri></li>
429     <li><uri link="http://www.alsa-project.org/documentation.php3">ALSA Users Documentation</uri></li>
430     <li><uri link="http://www.djcj.org">ALSA Howto's and FAQ's</uri></li>
431     <li><uri link="http://tldp.org/HOWTO/Sound-HOWTO/index.html">Linux Sound HOWTO</uri></li>
432     <li><uri link="http://linux-sound.org/">Sound and MIDI Software For Linux</uri></li>
433     </ul>
434     </p>
435     </body>
436     </section>
437     </chapter>
438     </guide>

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