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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 swift 1.18 <author title="Editor"><!-- zhen@gentoo.org -->
16     John P. Davis
17 drobbins 1.1 </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 swift 1.17 <version>1.3.3</version>
35     <date>October 9, 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 swift 1.17 <title>Gentoo USE flags</title>
99     <body>
100    
101     <p>
102     To compile programs with ALSA-support, be sure to add <e>alsa</e> to
103     your USE-variable. However, several tools don't support alsa yet, and
104     require OSS. ALSA provides OSS-emulation if you define <e>oss</e> in your
105     USE-variable before you start.
106     </p>
107    
108     </body>
109     </section>
110    
111     <section>
112 drobbins 1.1 <title>Kernel modules</title>
113     <body>
114     <p>
115 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.
116 drobbins 1.1 </p>
117     <p>
118     First we'll make sure that our kernel configuration is ready for use with ALSA.
119     All you need in your kernel configuration is having Sound Card Support set to be built as a module (M).
120     This will build <c>soundcore.o</c>.
121     </p>
122     <p>
123     <note>
124     Possibly, this will also work when you built Sound Card Support in the kernel (Y) instead of building it as a module (M).
125     However, the official ALSA documentation suggests building it as a module, since ALSA will try loading it.
126     </note>
127     </p>
128     <p>If you already have a working kernel configuration, make sure you remove all sound drivers (except for Sound Card Support).
129     If you wish to do this without having to reboot, you could do like this:
130     </p>
131     <pre>
132 blubber 1.16 # <i>cd /usr/src/linux</i>
133     # <i>cp .config ~/</i>
134     # <i>make mrproper</i>
135     # <i>cp ~/.config .</i>
136     # <i>make menuconfig</i>
137 drobbins 1.1 </pre>
138     <p>
139     Now select <e>Sound Card Support</e> as Module (M) and deselect all other sound drivers.
140     Exit and say Y to save your kernel configuration.
141     After that, build the modules:
142     </p>
143     <pre>
144 blubber 1.16 # <i>make dep clean</i>
145     # <i>make modules modules_install</i>
146 drobbins 1.1 </pre>
147     <p>
148     Before installing your new modules, this last line will delete all your previous modules,
149     even the ones from a previous ALSA installation.
150     </p>
151     <p>
152     <impo>
153     This means, whenever you recompile your kernel later on, you MUST recompile <c>alsa-driver</c>.
154     </impo>
155     </p>
156     <p>
157     <note>However, there's no need to reinstall <c>nvidia-kernel</c>, the Nvidia drivers are in a separate directory
158     in <path>/lib/modules/*/video</path> and won't get deleted by a <c>make modules modules_install</c>
159     </note>
160     </p>
161     </body>
162     </section>
163    
164     <section>
165     <title>ALSA modules</title>
166     <body>
167    
168     <p>
169     Now it's time to install the ALSA drivers for your soundcard(s). If your soundcard is PCI, you can find out the name
170 blubber 1.16 and type of your soundcard by looking at the output of /proc/pci.
171 drobbins 1.1 </p>
172 blubber 1.16 <pre>
173     # <i>grep audio /proc/pci</i>
174     </pre>
175    
176 drobbins 1.1
177     <p>
178     <warn>
179     If you had a previous sound setup and there are still non-ALSA sound modules loaded, unload them <e>now</e>.
180     Check with <c>lsmod</c> and use <c>rmmod</c> to unload all sound-related modules on your system.
181     </warn>
182     </p>
183    
184     <p>
185     We could simply do an <c>emerge alsa-driver</c> now, this would compile and install <e>all</e> ALSA sound drivers.
186     </p>
187     <p>
188     However, to save some time, lookup the <e>Module Name</e> of your soundcard(s) on the
189 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.
190     Mine is <c>snd-emu10k1</c>, since I have an SBlive! soundcard, with the <e>EMU10K1</e> chipset.
191     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.
192 drobbins 1.1 </p>
193    
194     <pre>
195 blubber 1.16 # <i>env ALSA_CARDS='emu10k1' emerge alsa-driver</i>
196 drobbins 1.1 </pre>
197     <note>
198 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>.
199     For example, like this: <c>echo 'ALSA_CARDS="emu10k1"' >> /etc/make.conf</c>
200     </note>
201    
202     <note>
203 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
204     of drivers; like this: <c>env ALSA_CARDS='emu10k1 intel8x0 ens1370' emerge alsa-driver</c>
205     </note>
206    
207     <note>If you want to have OSS compatibility, make sure to emerge <i>alsa-oss</i>, it is the ALSA/OSS compatibility
208     wrapper. </note>
209    
210 swift 1.13 <note>If you plan on recompiling your kernels numerous times, it might
211     be adviseable to emerge <c>alsa-driver</c> with <c>--buildpkg</c>. This
212     will create a binary package for it. Later, after recompiling your kernel,
213     you can just do <c>emerge --usepkg alsa-driver</c> which will install the
214     binary package instead of recompiling it completely.</note>
215    
216 drobbins 1.1 <p>
217     After this, the ALSA modules should be installed on your system.
218     </p>
219     </body>
220     </section>
221     <section>
222     <title>Configuration of ALSA</title>
223     <body>
224     <p>
225     Let's start configuring now to get ALSA working properly.
226     We'll need to edit some files, to let our system know about the freshly installed ALSA modules.
227     </p>
228 swift 1.12
229 drobbins 1.1 <p>
230 swift 1.12 First, install <c>alsa-utils</c> on your system:
231     </p>
232    
233     <pre caption = "Emerging alsa-utils">
234     # <i>emerge alsa-utils</i>
235     </pre>
236    
237     <p>
238     Hereafter, we need to edit <path>/etc/modules.d/alsa</path>.
239 drobbins 1.1 </p>
240     <warn>
241     There is no need to edit <path>/etc/modules.conf</path>. Instead, always edit files in <path>/etc/modules.d</path>.
242     </warn>
243     <p>
244 zhen 1.7 Check the ALSA portion <e>at the bottom of the file</e>.
245     By tweaking this line you can specify the max number of soundcards you have (generally, just one).
246 drobbins 1.1 </p>
247 seo 1.8 <pre caption="At the bottom of /etc/modules.d/alsa">
248 blubber 1.16 <comment>Set this to the correct number of cards.</comment>
249     options snd cards_limit=1
250 drobbins 1.1 </pre>
251     <p>
252     Now we'll specify the sounddriver(s) ALSA should use. In the same file, edit like this:
253 blubber 1.16 </p>
254 seo 1.8 <pre caption="In /etc/modules.d/alsa">
255 bennyc 1.14 ## and then run `modules-update' command.
256 drobbins 1.1 ## Read alsa-driver's INSTALL file in /usr/share/doc for more info.
257     ##
258     ## ALSA portion
259 blubber 1.16 alias snd-card-0 snd-emu10k1
260     <comment>## If you have more than one, add:</comment>
261 drobbins 1.1 ## alias snd-card-1 snd-intel8x0
262 blubber 1.16 ## alias snd-card-2 snd-ens1370
263 drobbins 1.1 ## OSS/Free portion
264     ## alias sound-slot-0 snd-card-0
265     ## alias sound-slot-1 snd-card-1
266     ##
267     </pre>
268     <note>
269 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.
270 drobbins 1.1 I don't have experience with this, but you can find examples for configurations with two or more soundcards in
271     <uri link="http://www.alsa-project.org/alsa-doc/alsa-howto/c1660.htm">Chapter 6</uri>
272     of the <uri link="http://www.alsa-project.org/alsa-doc/alsa-howto/alsa-howto.html">ALSA Howto</uri>.
273     </note>
274     <p>
275 seo 1.8 Last thing to do in this file, almost at the end, check if these lines are there and uncommented:
276 blubber 1.16 </p>
277 seo 1.8 <pre caption="Near the end of /etc/modules.d/alsa">
278 drobbins 1.1 alias /dev/mixer snd-mixer-oss
279     alias /dev/dsp snd-pcm-oss
280     alias /dev/midi snd-seq-oss
281     </pre>
282     <p>
283 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>.
284 drobbins 1.1 <pre>
285 bennyc 1.14 # <i>modules-update</i>
286 drobbins 1.1 </pre>
287     </p>
288     <note>
289 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>
290 drobbins 1.1 </note>
291     <p>
292     You should also verify that /etc/devfsd.conf has the alsa devices and permissions correctly registered.
293     </p>
294 seo 1.8 <pre caption="/etc/devfsd.conf">
295 drobbins 1.1 # ALSA/OSS stuff
296     # Comment/change these if you want to change the permissions on
297     # the audio devices
298     LOOKUP snd MODLOAD ACTION snd
299     LOOKUP dsp MODLOAD
300     LOOKUP mixer MODLOAD
301     LOOKUP midi MODLOAD
302     REGISTER sound/.* PERMISSIONS root.audio 660
303     REGISTER snd/.* PERMISSIONS root.audio 660
304     </pre>
305     <note>
306     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.
307     </note>
308     </body>
309     </section>
310     </chapter>
311     <chapter>
312     <title>Starting ALSA</title>
313     <section>
314     <title>Adding alsasound to a runlevel</title>
315     <body>
316     <p>
317     First thing to do now, is to make ALSA startup at boottime. Like this:
318     <pre>
319 blubber 1.16 # <i>rc-update add alsasound boot</i>
320 drobbins 1.1 </pre>
321     </p>
322     <p>
323     <warn>Note that the alsasound script should be added to the "boot" runlevel, not the "default" runlevel.</warn>
324     </p>
325     </body>
326     </section>
327     <section>
328     <title>Running and unmuting</title>
329     <body>
330     <p>
331     Since we're Linux users, we don't want to reboot. So we'll start the alsasound script manually.
332     </p>
333     <pre>
334 blubber 1.16 # <i>/etc/init.d/alsasound start</i>
335 drobbins 1.1 </pre>
336     <p>
337     ALSA is running now. If everything is ok, you should be able to see the ALSA modules loaded when running <c>lsmod</c>.
338 swift 1.12 However, sound won't work yet, because the channels are still muted. We need <c>amixer</c> for this.
339 drobbins 1.1 </p>
340 swift 1.12 <pre caption = "Running amixer">
341     # <i>amixer</i>
342 drobbins 1.1 </pre>
343     <p>
344     <warn>
345 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
346 drobbins 1.1 <c>snd-mixer-oss</c> and <c>snd-pcm-oss</c> once. After that run amixer again.
347     </warn>
348     </p>
349     <pre caption="only if you get an error when running amixer">
350 bennyc 1.15 # <i>modprobe snd-mixer-oss</i>
351     # <i>modprobe snd-pcm-oss</i>
352     # <i>amixer</i>
353 drobbins 1.1 </pre>
354     <p>
355 swift 1.13 If you got this far, now unmute Master and PCM channels. Some hardware
356     even requires you to unmute the center channel or even the surround
357     channel.
358 drobbins 1.1 </p>
359     <p>
360 swift 1.13 <pre caption = "Unmuting channels">
361     # <i>amixer set Master 100 unmute</i>
362     # <i>amixer set PCM 100 unmute</i>
363     <comment>Only if the above doesn't succeed on its own:</comment>
364     # <i>amixer set Center 100 unmute</i>
365     # <i>amixer set Surround 100 unmute</i>
366     <comment>Test the sound:</comment>
367     # <i>aplay $KDEDIR/share/sounds/pop.wav</i> <codenote>(pop.wav is part of KDE)</codenote>
368 drobbins 1.1 </pre>
369     </p>
370     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.
371     Then, adjust the volume settings to your liking; the ncurses-based <c>alsamixer</c> is a great way to get them "just so".
372     <p>
373     You may want to emerge <c>alsa-xmms</c> as that will provide ALSA support for XMMS.
374     </p>
375     When you reboot your system, the <e>alsasound</e> init script will properly save and restore your volume settings.
376     </body>
377     </section>
378     </chapter>
379     <chapter>
380     <title>Final Notes</title>
381     <section>
382     <title>After kernel-upgrades..</title>
383     <body>
384     <p>When you ever rebuild your kernel, or upgrade to another kernel, you'll have to rebuild the ALSA modules.</p>
385     <p>Although you might have installed <c>alsa-driver</c>, <c>alsa-libs</c> and <c>alsa-utils</c>, only the first will
386     have to be installed again, since it will put the alsa modules in
387     <path>/lib/modules/*/kernel/sound/pci/</path>.</p>
388     <pre caption="needed after each kernel compile">
389 blubber 1.16 # <i>emerge alsa-driver</i>
390 drobbins 1.1 </pre>
391     </body>
392     </section>
393     <section>
394     <title>/etc/modules.autoload</title>
395     <body>
396     <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
397     load the correct modules at startup.</p>
398     <p>It's not necessary to add <c>snd-pcm-oss</c> or <c>snd-mixer-oss</c> in this file.
399     Check the <uri link="http://www.djcj.org/LAU/guide/alsbook/faq1.html">this FAQ</uri> for more info.</p>
400     </body>
401     </section>
402 swift 1.17
403     <section>
404     <title>Known bugs</title>
405     <body>
406    
407     <note>
408     This guide lags behind on the alsa-development. Chances are these bugs
409     are already fixed when you read this.
410     </note>
411    
412     <ul>
413     <li>
414     If you have <b>lots of noise</b> when using <b>oss</b> emulation, add
415     <e>options snd-pcm-oss dsp_map=1</e> to
416     <path>/etc/modules.d/alsa</path>.
417     </li>
418     </ul>
419    
420     </body>
421     </section>
422    
423 drobbins 1.1 <section>
424     <title>More links..</title>
425     <body>
426     <p>
427     You could check these for additional info:
428     </p>
429     <p>
430     <ul>
431 seo 1.8 <li><uri link="http://www.gentoo.org/doc/en/desktop.xml">The Gentoo Linux Desktop Configuration Guide</uri></li>
432 drobbins 1.1 <li><uri link="http://www.alsa-project.org">ALSA Project Homepage</uri></li>
433     <li><uri link="http://www.alsa-project.org/documentation.php3">ALSA Users Documentation</uri></li>
434     <li><uri link="http://www.djcj.org">ALSA Howto's and FAQ's</uri></li>
435     <li><uri link="http://tldp.org/HOWTO/Sound-HOWTO/index.html">Linux Sound HOWTO</uri></li>
436     <li><uri link="http://linux-sound.org/">Sound and MIDI Software For Linux</uri></li>
437     </ul>
438     </p>
439     </body>
440     </section>
441     </chapter>
442     </guide>

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