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1<?xml version='1.0' encoding="UTF-8"?> 1<?xml version='1.0' encoding="UTF-8"?>
2<!-- $Header: /var/cvsroot/gentoo/xml/htdocs/doc/en/alsa-guide.xml,v 1.73 2007/02/17 19:03:36 nightmorph Exp $ -->
3
2<!DOCTYPE guide SYSTEM "/dtd/guide.dtd"> 4<!DOCTYPE guide SYSTEM "/dtd/guide.dtd">
3 5
4<guide link = "/doc/en/alsa-guide.xml"> 6<guide link="/doc/en/alsa-guide.xml">
5<title>Gentoo Linux ALSA Guide</title> 7<title>Gentoo Linux ALSA Guide</title>
6<author title="Author"><mail link="zu@pandora.be"> 8
7 Vincent Verleye</mail> 9<author title="Author">
10 <mail link="fox2mike@gentoo.org">Shyam Mani</mail>
8</author> 11</author>
9 12<author title="Author">
10<author title="Editor"><mail link="zhen@gentoo.org"> 13 <mail link="nightmorph@gentoo.org">Joshua Saddler</mail>
11 John P. Davis</mail>
12</author> 14</author>
15<author title="Contributor">
16 <mail link="flameeyes@gentoo.org">Diego Pettenò</mail>
17</author>
13 18
14<abstract> 19<abstract>
15This guide will show you how to set up the Advanced Linux Sound Architecture (ALSA) on Gentoo Linux. 20This document helps a user setup ALSA on Gentoo Linux.
16In addition to the Gentoo Linux Desktop Configuration Guide, this guide is supposed to give you more information on this subject. </abstract> 21</abstract>
17 22
23<!-- The content of this document is licensed under the CC-BY-SA license -->
24<!-- See http://creativecommons.org/licenses/by-sa/2.5 -->
25<license/>
26
18<version>1.2</version> 27<version>2.17</version>
19<date>09 February 2003</date> 28<date>2007-02-17</date>
20 29
21<chapter> 30<chapter>
22<title>Introduction</title> 31<title>Introduction</title>
23<section> 32<section>
24 <title>What is ALSA?</title> 33<title>What is ALSA?</title>
34<body>
35
36<p>
37ALSA, which stands for <e>Advanced Linux Sound Architecture</e>, provides
38audio and MIDI (<e>Musical Instrument Digital Interface</e>) functionality to
39the Linux operating system. ALSA is the default sound subsystem in the 2.6
40kernel thereby replacing OSS (<e>Open Sound System</e>), which was used in the
412.4 kernels.
42</p>
43
44<p>
45ALSA's main features include efficient support for all types of audio
46interfaces ranging from consumer sound cards to professional sound
47equipment, fully modularized drivers, SMP and thread safety, backward
48compatibility with OSS and a user-space library <c>alsa-lib</c> to make
49application development a breeze.
50</p>
51
25<body> 52</body>
26<p> 53</section>
27The Advanced Linux Sound Architecture (ALSA) is a project to improve the Linux sound subsystem by rewriting 54<section>
28large chunks of it. 55<title>ALSA on Gentoo</title>
29It is anticipated that ALSA will make it into Linux kernel 2.6.x (or 3.x.x -- whichever comes first) as it becomes ready. 56<body>
57
30</p> 58<p>
31 59One of Gentoo's main strengths lies in giving the user maximum control over
60how a system is installed/configured. ALSA on Gentoo follows the same
61principle. There are two ways you can get ALSA support up and running on your
62system. We shall look at them in detail in the next chapter.
32<p> 63</p>
33ALSA provides audio and MIDI functionality for Linux. 64
65</body>
66</section>
67</chapter>
68
69<chapter>
70<title>Installing ALSA</title>
71<section>
72<title>Options</title>
73<body>
74
75<warn>
76The methods shown below are mutually exclusive. You cannot have ALSA compiled
77in your kernel and use <c>media-sound/alsa-driver</c>. It <e>will</e> fail.
78</warn>
79
34</p> 80<p>
35 81The two options are :
36<p> 82</p>
37Quoted from <uri>http://www.alsa-project.org</uri>, ALSA has the following features: 83
38<ul><li> Efficient support for all types of audio interfaces, from consumer soundcards to professional multichannel audio interfaces.</li> 84<ol>
39 <li> Fully modularized sound drivers.</li> 85 <li>Use ALSA provided by your kernel.</li>
40 <li> SMP and thread-safe design.</li> 86 <li>Use Gentoo's <c>media-sound/alsa-driver</c> package.</li>
41 <li> User space library (alsa-lib) to simplify application programming and provide higher level functionality.</li> 87</ol>
42 <li> Support for the older OSS API, providing binary compatibility for most OSS programs.</li> 88
89<p>
90The in-kernel drivers and the <c>alsa-driver</c> package can vary a little; it's
91possible that features and fixes found in one might not yet be incorporated into
92the other. The upstream developers are aware of this, but the two drivers are
93effectively separate branches of the ALSA project; they are not entirely
94identical. You should be aware that they might function slightly differently, so
95if one doesn't work for you, try the other! We shall take a peek into both
96before finally deciding on one.
97</p>
98
99<p>
100If you were to use ALSA provided by the kernel, the following are the pros and
101cons :
102</p>
103
104<table>
105<tr>
106 <th>Kernel ALSA</th>
107 <th>Pros and Cons</th>
108</tr>
109<tr>
110 <th>+</th>
111 <ti>
112 No need to emerge yet another package; drivers are integrated into kernel.
113 </ti>
114</tr>
115<tr>
116 <th>+</th>
117 <ti>One shot solution, no repeating emerges.</ti>
118</tr>
119<tr>
120 <th>-</th>
121 <ti>Might be a slightly different version than <c>alsa-driver</c>.</ti>
122</tr>
123</table>
124
125<p>
126And, if you were to use alsa-driver,
127</p>
128
129<table>
130<tr>
131 <th>alsa-driver</th>
132 <th>Pros and Cons</th>
133</tr>
134<tr>
135 <th>+</th>
136 <ti>Possibly the latest drivers from the ALSA Project.</ti>
137</tr>
138<tr>
139 <th>+</th>
140 <ti>Useful if you intend to develop audio drivers.</ti>
141</tr>
142<tr>
143 <th>-</th>
144 <ti>Every kernel recompile requires a re-emerge of <c>alsa-driver</c>.</ti>
145</tr>
146<tr>
147 <th>-</th>
148 <ti>Needs certain kernel config options disabled to work correctly.</ti>
149</tr>
150</table>
151
152</body>
153</section>
154<section>
155<title>So...</title>
156<body>
157
158<p>
159The differences between <c>alsa-driver</c> and the in-kernel ALSA drivers are
160quite subtle, as mentioned earlier. Since there are not any huge differences,
161this guide will go through the process of using the ALSA provided by the kernel
162<e>first</e> for ease of use. However, if you run into problems, try switching
163to <c>alsa-driver</c>. Before reporting any sound related issues to <uri
164link="https://bugs.gentoo.org">Gentoo Bugzilla</uri>, please try to reproduce
165them using <c>alsa-driver</c> and file the bug report no matter what the
166result.
167</p>
168
169</body>
170</section>
171<section id="lspci">
172<title>Before you proceed</title>
173<body>
174
175<p>
176Whichever method of install you choose, you need to know what drivers your
177sound card uses. In most cases, sound cards (onboard and otherwise) are PCI
178based and <c>lspci</c> will help you in digging out the required information.
179Please <c>emerge sys-apps/pciutils</c> to get <c>lspci</c>, if you don't have it
180installed already. In case you have a USB sound card, <c>lsusb</c> from
181<c>sys-apps/usbutils</c> <e>might</e> be of help. For ISA cards, try using
182<c>sys-apps/isapnptools</c>. Also, the following pages <e>may</e> help users
183with ISA based sound cards.
184</p>
185
186<ul>
187 <li>
188 <uri link="http://www.roestock.demon.co.uk/isapnptools/">The ISAPNPTOOLS
189 Page</uri>
190 </li>
191 <li>
192 <uri link="http://www2.linuxjournal.com/article/3269">LinuxJournal PnP
193 Article</uri>
194 </li>
195 <li>
196 <uri link="http://www.tldp.org/HOWTO/Sound-HOWTO/x320.html">TLDP Sound
197 HowTo</uri>
198 </li>
43</ul> 199</ul>
44There's lots more to ALSA however, like support for Full Duplex playback and recording, multiple soundcard support, 200
45hardware mixing of streams, extensive mixer capabilities (to support advanced features of new soundcards), ... 201<note>
202For ease of use/explanation, we assume the user has a PCI based sound card for
203the remainder of this guide.
204</note>
205
46</p> 206<p>
207We now proceed to find out details about the sound card.
208</p>
209
210<pre caption="Soundcard Details">
211# <i>lspci -v | grep -i audio</i>
2120000:00:0a.0 Multimedia audio controller: Creative Labs SB Live! EMU10k1 (rev 06)
213</pre>
214
215<p>
216We now know that the sound card on the machine is a Sound Blaster Live! and
217the card manufacturer is Creative Labs. Head over to the
218<uri link="http://www.alsa-project.org/alsa-doc/"> ALSA Soundcard Matrix</uri>
219page and select Creative Labs from the drop down menu. You will be taken to
220the Creative Labs matrix page where you can see that the SB Live! uses the
221<c>emu10k1</c> module. That is the information we need for now. If you are
222interested in detailed information, you can click on the link next to the
223"Details" and that will take you to the <c>emu10k1</c> specific page.
224</p>
225
226<p>
227If you intend to use MIDI, then you should add <c>midi</c> to your USE flags in
228<path>/etc/make.conf</path> before emerging any ALSA packages. Later in the
229guide, we will show you how to set up <uri link="#midi">MIDI support</uri>.
230</p>
231
232<pre caption="MIDI support in /etc/make.conf">
233<comment>(If you want MIDI support)</comment>
234USE="midi"
235
236<comment>(If you don't need MIDI)</comment>
237USE="-midi"
238</pre>
239
47</body> 240</body>
48</section>
49<section> 241</section>
50 <title>Why use ALSA?</title> 242<section id="kernel">
51<body> 243<title>Using ALSA provided by your Kernel</title>
52<p>
53If your soundcard is supported by the Linux kernel sound system or the commercial OSS/4Front sound driver system,
54which can be found in all 2.4.x Linux kernels, you could just aswell build <e>those modules</e> for use with your soundcard.
55If 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>
58However, those OSS/4Front drivers have some limitations -- being commercial is one.
59ALSA is an attempt to go beyond these limitations and to do so in an open source fashion.
60ALSA is a fully GPL and LGPL'ed sound driver system, that provides a professional quality system for recording, playback,
61and MIDI sequencing.
62</p>
63</body> 244<body>
64</section> 245
246<p>
247If you're a person who likes to keep things simple like I do, then this is
248the way to go.
249</p>
250
251<note>
252Since the 2005.0 release, Gentoo Linux uses 2.6 as the default kernel. Unless
253you are specifically using the 2.4 profile, <c>gentoo-sources</c> will be a
2542.6 kernel on <e>most</e> architectures. Please check that your kernel is a
2552.6 series kernel. This method will <e>not</e> work on a 2.4 kernel.
256</note>
257
258<p>
259Let us now configure the kernel to enable ALSA.
260</p>
261
262<impo>
263<c>genkernel</c> users should now run <c>genkernel --menuconfig all</c> and
264then follow the instructions in <uri link="#doc_chap2_pre3">Kernel Options for
265ALSA</uri>.
266</impo>
267
268<pre caption="Heading over to the source">
269# <i>cd /usr/src/linux</i>
270# <i>make menuconfig</i>
271</pre>
272
273<note>
274The above example assumes that <path>/usr/src/linux</path> symlink points to
275the kernel sources you want to use. Please ensure the same before proceeding.
276</note>
277
278<p>
279Now we will look at some of the options we will have to enable in the 2.6
280kernel to ensure proper ALSA support for our sound card.
281</p>
282
283<p>
284Please note that for ease of use, all examples show ALSA built as modules. It
285is advisable to follow the same as it then allows the use of <c>alsaconf</c>
286which is a boon when you want to configure your card. Please do <e>not</e> skip
287the <uri link="#alsa-config">Configuration</uri> section of this document. If
288you still like to have options built-in, ensure that you make changes to your
289config accordingly.
290</p>
291
292<pre caption="Kernel Options for ALSA">
293Device Drivers ---&gt;
294 Sound ---&gt;
295
296<comment>(This needs to be enabled)</comment>
297&lt;M&gt; Sound card support
298
299<comment>(Make sure OSS is disabled)</comment>
300Open Sound System ---&gt;
301 &lt; &gt; Open Sound System (DEPRECATED)
302
303<comment>(Move one step back and enter ALSA)</comment>
304Advanced Linux Sound Architecture ---&gt;
305 &lt;M&gt; Advanced Linux Sound Architecture
306 <comment>(Select this if you want MIDI sequencing and routing)</comment>
307 &lt;M&gt; Sequencer support
308 <comment>(Old style /dev/mixer* and /dev/dsp* support. Recommended.)</comment>
309 &lt;M&gt; OSS Mixer API
310 &lt;M&gt; OSS PCM (digital audio) API
311
312<comment>(You now have a choice of devices to enable support for. Generally,
313you will have one type of device and not more. If you have more than one
314sound card, please enable them all here.)</comment>
315
316<comment>(Mostly for testing and development purposes, not needed for normal
317users unless you know what you are doing.)</comment>
318Generic devices ---&gt;
319
320<comment>(For ISA Sound cards)</comment>
321ISA devices ---&gt;
322<comment>(IF you had the Gravis, you would select this option)</comment>
323 &lt;M&gt; Gravis UltraSound Extreme
324
325<comment>(Move one level back and into PCI devices. Most sound cards today are
326PCI devices)</comment>
327PCI devices ---&gt;
328 <comment>(We now select the emu10k1 driver for our card)</comment>
329 &lt;M&gt; Emu10k1 (SB Live!, Audigy, E-mu APS)
330 <comment>(Or an Intel card would be)</comment>
331 &lt;M&gt; Intel/SiS/nVidia/AMD/ALi AC97 Controller
332 <comment>(Or if you have a VIA Card)</comment>
333 &lt;M&gt; VIA 82C686A/B, 8233/8235 AC97 Controller
334
335<comment>(Move one level back and select in case you have an USB sound card)</comment>
336USB Devices ---&gt;
337</pre>
338
339<p>
340Now that your options are set, you can (re)compile the kernel and ALSA support
341for your card should be functional once you reboot into the new kernel. Don't
342forget to update your GRUB configuration to use the newly built kernel.
343You can now proceed to <uri link="#alsa-utilities">ALSA Utilities</uri> and
344see if everything is working as it should.
345</p>
346
347</body>
65<section> 348</section>
66 <title>What cards does ALSA support?</title> 349<section id="alsa-driver">
350<title>Using the ALSA Driver package</title>
67<body> 351<body>
68<p> 352
69ALSA tries to support as many (new) cards as possible by providing open-source drivers.
70However, some vendors may provide binary-only packages.
71</p> 353<p>
72<p>To know if your card is supported, you can find a Soundcard Matrix of supported and not-supported cards here: 354So you've decided to go the <c>alsa-driver</c> way. Let's get started then.
73<uri>http://www.alsa-project.org/alsa-doc/</uri>. 355There are a few minor things to be done to ensure only the drivers for your
356sound card are compiled. Although this is not really necessary, it cuts down
357on the unnecessary drivers that will be compiled otherwise.
358</p>
359
74</p> 360<p>
361If you don't have an idea of what drivers your sound card might need, please
362take a look at the <uri link="#lspci">lspci</uri> section of this guide. Once
363you have your driver name (<c>emu10k1</c> in our example), edit
364<path>/etc/make.conf</path> and add a variable, <c>ALSA_CARDS</c>.
365</p>
366
367<pre caption="Adding ALSA_CARDS to make.conf">
368<comment>(For one sound card)</comment>
369ALSA_CARDS="emu10k1"
370<comment>(For more than one, separate names with spaces)</comment>
371ALSA_CARDS="emu10k1 via82xx"
372</pre>
373
374<p>
375If you have compiled your kernel and want to use <c>alsa-driver</c>, please
376ensure the following before proceeding, else <c>alsa-driver</c> is likely to
377fail. The next code listing gives you one way of performing the checks.
378</p>
379
380<note>
381<c>genkernel</c> users can proceed with <uri link="#doc_chap2_pre6">Installing
382alsa-driver</uri> as their configuration is in sync with the one shown below by
383default.
384</note>
385
386<ol>
387 <li>
388 <c>CONFIG_SOUND</c> is set. (Basic Sound support enabled)
389 </li>
390 <li>
391 <c>CONFIG_SOUND_PRIME</c> is not set. (In-built OSS support disabled)
392 </li>
393 <li>
394 <c>CONFIG_SND</c> is not set. (In-built ALSA support disabled)
395 </li>
396 <li>
397 <path>/usr/src/linux</path> points to the kernel you want ALSA working on.
398 </li>
399</ol>
400
401<pre caption=".config checks">
402<comment>(Assuming the linux symlink points to the correct kernel)</comment>
403# <i>cd /usr/src/linux</i>
404# <i>grep SOUND .config</i>
405<comment>(1. is true)</comment>
406CONFIG_SOUND=y
407<comment>(2. is true)</comment>
408CONFIG_SOUND_PRIME is not set
409# <i>grep SND .config</i>
410<comment>(and 3. is true)</comment>
411CONFIG_SND is not set
412</pre>
413
414<p>
415Now all you have to do is type the magic words... and no, it's not abracadabra.
416</p>
417
418<pre caption="Installing alsa-driver">
419# <i>emerge alsa-driver</i>
420</pre>
421
422<impo>
423Please note that you will have to run <c>emerge alsa-driver</c> after every
424kernel (re)compile, as the earlier drivers are deleted. To make this task
425easier, you may want to emerge the <c>module-rebuild</c> package, which will
426keep track of module packages and rebuild them for you. First run
427<c>module-rebuild populate</c> to create the list, and then after every kernel
428(re)compile, you just run <c>module-rebuild rebuild</c>, and your external
429modules will be rebuilt.
430</impo>
431
75</body> 432</body>
76</section> 433</section>
77</chapter> 434</chapter>
78 435
79<chapter> 436<chapter>
80<title>Installation</title> 437<title>Configuring/Testing ALSA</title>
81<section> 438<section id="alsa-utilities">
82 <title>Kernel modules</title> 439<title>ALSA Utilities</title>
83<body> 440<body>
84<p> 441
85Since we're still using 2.4.x kernel sources, we'll have to compile kernel modules and ALSA modules separately.
86</p> 442<p>
443<c>alsa-utils</c> forms an integral part of ALSA as it has a truckload of
444programs that are highly useful, including the ALSA Initscripts. Hence we
445strongly recommend that you install <c>alsa-utils</c>
87<p> 446</p>
88First we'll make sure that our kernel configuration is ready for use with ALSA. 447
89All you need in your kernel configuration is having Sound Card Support set to be built as a module (M). 448<pre caption="Install alsa-utils">
90This will build <c>soundcore.o</c>. 449# <i>emerge alsa-utils</i>
91</p> 450</pre>
92<p> 451
93<note> 452<note>
94Possibly, this will also work when you built Sound Card Support in the kernel (Y) instead of building it as a module (M). 453If you activated ALSA in your <uri link="#kernel">kernel</uri> <e>and</e> did
95However, the official ALSA documentation suggests building it as a module, since ALSA will try loading it. 454not compile ALSA as modules, please proceed to the
455<uri link="#initscript">ALSA Initscript</uri> section. The rest of you need
456to configure ALSA. This is made very easy by the existence of the
457<c>alsaconf</c> tool provided by <c>alsa-utils</c>.
96</note> 458</note>
459
460</body>
461</section>
462<section id="alsa-config">
463<title>Configuration</title>
464<body>
465
97</p> 466<p>
98<p>If you already have a working kernel configuration, make sure you remove all sound drivers (except for Sound Card Support). 467Recent versions of <c>udev</c> (<c>>=udev-103</c>) provide some degree of
99If you wish to do this without having to reboot, you could do like this: 468kernel-level autoconfiguration of your sound card. If possible, try to rely on
469just letting your kernel automatically setup your sound card for you. Otherwise,
470use <c>alsaconf</c> to configure your card, as shown below.
471</p>
472
473<note>
474Please shut down any programs that <e>might</e> access the sound card while
475running <c>alsaconf</c>.
476</note>
477
100</p> 478<p>
479Another way to configure your sound card is to run <c>alsaconf</c>. Just type
480<c>alsaconf</c> in a shell as root.
481</p>
482
483<pre caption="Invoking alsaconf">
484# <i>alsaconf</i>
101<pre> 485</pre>
102# <c>cd /usr/src/linux</c> 486
103# <c>cp .config ~/</c>
104# <c>make mrproper</c>
105# <c>cp ~/.config .</c>
106# <c>make menuconfig</c>
107</pre>
108<p>
109Now select <e>Sound Card Support</e> as Module (M) and deselect all other sound drivers.
110Exit and say Y to save your kernel configuration.
111After that, build the modules:
112</p> 487<p>
488You will now see a neat menu guided interface that will automatically probe
489your devices and try to find out your sound card. You will be asked to pick
490your sound card from a list. Once that's done, it will ask you permission to
491automatically make required changes to <path>/etc/modules.d/alsa</path>.
492It will then adjust your volume settings to optimum levels, run
493<c>modules-update</c> and start the <path>/etc/init.d/alsasound</path> service.
494Once <c>alsaconf</c> exits, you can proceed with setting up the ALSA
495initscript.
496</p>
497
498</body>
499</section>
500<section id="initscript">
501<title>ALSA Initscript</title>
502<body>
503
504<p>
505We're now almost all setup. Whichever method you chose to install ALSA, you'll
506need to have something load your modules or initialize ALSA and restore your
507volume settings when your system comes up. The ALSA Initscript handles all of
508this for you and is called <c>alsasound</c>. Add it to the boot runlevel.
509</p>
510
511<pre caption="Adding ALSA to the boot runlevel">
512# <i>rc-update add alsasound boot</i>
513 * alsasound added to runlevel boot
514 * rc-update complete.
113<pre> 515</pre>
114# <c>make dep clean</c> 516
115# <c>make modules modules_install</c>
116</pre>
117<p>
118Before installing your new modules, this last line will delete all your previous modules,
119even the ones from a previous ALSA installation.
120</p> 517<p>
518Next, just check the <path>/etc/conf.d/alsasound</path> file and ensure that
519SAVE_ON_STOP variable is set to yes. This saves your sound settings when you
520shutdown your system.
121<p> 521</p>
522
523</body>
524</section>
525<section>
526<title>Audio Group</title>
527<body>
528
529<p>
530Before we move on to testing, there's one last <e>important</e> thing that needs
531to be setup. Rule of thumb in a *nix OS : Do not run as root unless needed.
532This applies here as well ;) How? Well, most of the times you should be logged
533in as a user and would like to listen to music or access your soundcard. For
534that to happen, you need to be in the "audio" group. At this point, we'll add
535users to the audio group, so that they won't have any issues when they want to
536access sound devices. We'll use <c>gpasswd</c> here and you need to be logged in
537as root for this to work.
538</p>
539
540<pre caption="Adding users to the audio group">
541<comment>(Substitute &lt;username&gt; with your user)</comment>
542# <i>gpasswd -a &lt;username&gt; audio </i>
543Adding user &lt;username&gt; to group audio
544</pre>
545
546</body>
547</section>
548<section>
549<title>Volume Check!</title>
550<body>
551
552<p>
553We've completed all the setups and prerequisites, so let's fire up ALSA. If
554you ran <c>alsaconf</c>, you can skip this step, since <c>alsaconf</c> already
555does this for you.
556</p>
557
558<pre caption="Start the service">
559# <i>/etc/init.d/alsasound start</i>
560</pre>
561
562<p>
563Now that the required things have been taken care of, we need to check up on
564the volume as in certain cases, it is muted. We use <c>alsamixer</c> for this
565purpose.
566</p>
567
568<pre caption="Starting alsamixer">
569<comment>(Opens up a console program. Only required settings are shown)</comment>
570# <i>alsamixer</i>
571</pre>
572
122<impo> 573<impo>
123This means, whenever you recompile your kernel later on, you MUST recompile <c>alsa-driver</c>. 574If you have issues starting up <c>alsamixer</c> and get errors such as
575alsamixer: function snd_ctl_open failed for default: No such file or directory,
576this is usually an issue with udev setting up the devices. Run <c>killall
577udevd; udevstart</c> to reload <path>/dev</path> entries and fire up
578<c>alsamixer</c>. It should solve the issue.
124</impo> 579</impo>
580
125</p> 581<p>
582This is how the ALSA Mixer <e>might</e> look the first time you open it. Pay
583attention to the Master and PCM channels which both have an MM below them.
584That means they are muted. If you try to play anything with <c>alsamixer</c>
585in this state, you will not hear anything on your speakers.
126<p> 586</p>
127<note>However, there's no need to reinstall <c>nvidia-kernel</c>, the Nvidia drivers are in a separate directory 587
128in <path>/lib/modules/*/video</path> and won't get deleted by a <c>make modules modules_install</c> 588<figure link="/images/docs/alsa-mixermuted.png" short="AlsaMixer Muted" caption="The Alsa Mixer Main Window, Muted"/>
589
590<p>
591Now, we shall unmute the channels, and set volume levels as needed.
592</p>
593
594<warn>
595Both Master <e>and</e> PCM need to be unmuted and set to audible volume levels
596if you want to hear some output on your speakers.
597</warn>
598
599<ul>
600 <li>
601 To move between channels, use your left and right arrow keys. (&lt;-
602 &amp; -&gt;)
603 </li>
604 <li>
605 To toggle mute, move to the specific channel, for example Master and press
606 the <e>m</e> key on the keyboard.
607 </li>
608 <li>
609 To increase and decrease the volume levels, use the up and down arrow keys
610 respectively.
611 </li>
612</ul>
613
614<note>
615Be careful when setting your Bass and Treble values. 50 is usually a good
616number for both. Extremely high values of Bass may cause <e>jarring</e>
617on speakers that are not designed to handle them.
129</note> 618</note>
619
130</p> 620<p>
131</body> 621After you're all done, your ALSA Mixer should look similar to the one below.
132</section> 622Note the 00 instead of the MM and also the volume levels for some optimum
623settings.
624</p>
133 625
626<figure link="/images/docs/alsa-mixerunmuted.png" short="AlsaMixer Unmuted" caption="Alsa Mixer ready to roll"/>
627
628</body>
134<section> 629</section>
135 <title>ALSA modules</title> 630<section>
631<title>Sound Check!</title>
632<body>
633
634<p>
635Finally. Some music. If everything above is perfect, you should now be able to
636listen to some good music. A quick way to test is to use a command line tool
637like <c>media-sound/madplay</c>. You could also use something more well known
638like <c>mpg123</c>. If you are an ogg fan, you could use <c>ogg123</c> provided
639by <c>media-sound/vorbis-tools</c>. Use any player you are comfortable with. As
640always, <c>emerge</c> what you need.
641</p>
642
643<pre caption="Getting the software">
644<comment>(Install the applications you want)</comment>
645# <i>emerge madplay mpg123</i>
646<comment>(To play .ogg files)</comment>
647# <i>emerge vorbis-tools</i>
648</pre>
649
650<p>
651And then play your favorite sound track...
652</p>
653
654<pre caption="Playing Music">
655# <i>madplay -v /mnt/shyam/Music/Paul\ Oakenfold\ -\ Dread\ Rock.mp3</i>
656MPEG Audio Decoder 0.15.2 (beta) - Copyright (C) 2000-2004 Robert Leslie et al.
657 Title: Dread Rock
658 Artist: Paul Oakenfold
659 Album: Matrix Reloaded
660 Year: 2003
661 Genre: Soundtrack
662 Soundtrack
663 00:04:19 Layer III, 160 kbps, 44100 Hz, joint stereo (MS), no CRC
664
665# <i>ogg123 Paul\ Oakenfold\ -\ Dread\ Rock.ogg</i>
666Audio Device: Advanced Linux Sound Architecture (ALSA) output
667
668Playing: Paul Oakenfold - Dread Rock.ogg
669Ogg Vorbis stream: 2 channel, 44100 Hz
670Genre: Soundtrack
671Transcoded: mp3;160
672Title: Dread Rock
673Artist: Paul Oakenfold
674Date: 2003
675Album: Matrix Reloaded
676Time: 00:11.31 [04:28.75] of 04:40.06 (200.6 kbps) Output Buffer 96.9%
677</pre>
678
136<body> 679</body>
680</section>
681<section>
682<title>ALSA and USE</title>
683<body>
137 684
138<p>
139Now it's time to install the ALSA drivers for your soundcard(s). If your soundcard is PCI, you can find out the name
140and type of your soundcard by looking at the output of /proc/pci
141<pre>#<c>grep audio /proc/pci</c></pre>
142</p> 685<p>
143 686You can now add the <c>alsa</c> use flag to <path>/etc/make.conf</path> to
687ensure that your applications that support ALSA get built with it. Some
688architectures like x86 and amd64 have the flag enabled by default.
144<p> 689</p>
145<warn> 690
146If you had a previous sound setup and there are still non-ALSA sound modules loaded, unload them <e>now</e>. 691</body>
147Check with <c>lsmod</c> and use <c>rmmod</c> to unload all sound-related modules on your system. 692</section>
148</warn> 693<section>
694<title>Issues?</title>
695<body>
696
149</p> 697<p>
150 698If for some reason you're unable to hear sound, the first thing to do would
699be to check your <uri link="#doc_chap3_pre6">alsamixer</uri> settings. 80% of
700the issues lie with muted channels or low volume. Also check your Window
701Manager's sound applet and verify that volumes are set to audible levels.
151<p> 702</p>
152We could simply do an <c>emerge alsa-driver</c> now, this would compile and install <e>all</e> ALSA sound drivers. 703
153</p> 704<p>
705<path>/proc</path> is your friend. And in this case, <path>/proc/asound</path>
706is your best friend. We shall just take a short look at how much info is made
707available to us there.
154<p> 708</p>
155However, 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.
157Mine is <c>EMU10K1</c>, since I have an SBlive! soundcard.
158We'll set ALSA_CARDS environment to this value before emerging, so emerge will only compile the drivers we need.
159</p>
160 709
161<p> 710<pre caption="Fun with /proc/asound">
711<comment>(First and foremost, if /proc/asound/cards shows your card, ALSA has
712picked up your sound card fine.)</comment>
713# <i>cat /proc/asound/cards</i>
7140 [Live ]: EMU10K1 - Sound Blaster Live!
715 Sound Blaster Live! (rev.6, serial:0x80271102) at 0xb800, irq 11
716
717<comment>(If you run ALSA off the kernel like I do and wonder how far behind
718you are from alsa-driver, this displays current running ALSA version)</comment>
719# <i>cat /proc/asound/version</i>
720Advanced Linux Sound Architecture Driver Version 1.0.8 (Thu Jan 13 09:39:32 2005 UTC).
721
722<comment>(ALSA OSS emulation details)</comment>
723# <i>cat /proc/asound/oss/sndstat</i>
724Sound Driver:3.8.1a-980706 (ALSA v1.0.8 emulation code)
725Kernel: Linux airwolf.zion 2.6.11ac1 #2 Wed May 4 00:35:08 IST 2005 i686
726Config options: 0
727
728Installed drivers:
729Type 10: ALSA emulation
730
731Card config:
732Sound Blaster Live! (rev.6, serial:0x80271102) at 0xb800, irq 11
733
734Audio devices:
7350: EMU10K1 (DUPLEX)
736
737Synth devices: NOT ENABLED IN CONFIG
738
739Midi devices:
7400: EMU10K1 MPU-401 (UART)
741
742Timers:
7437: system timer
744
745Mixers:
7460: SigmaTel STAC9721/23
162<pre> 747</pre>
163# <c>env ALSA_CARDS='emu10k1' emerge alsa-driver</c> 748
164</pre>
165</p> 749<p>
750The other most common issue users face is the dreaded "Unknown symbol in module"
751error. An example of the same is shown below.
166<p> 752</p>
753
754<pre caption="Unknown Symbol in module error">
755# <i>/etc/init.d/alsasound start</i>
756 * Loading ALSA modules ...
757 * Loading: snd-card-0 ... [ ok ]
758 * Loading: snd-pcm-oss ...
759WARNING: Error inserting snd_mixer_oss
760(/lib/modules/2.6.12-gentoo-r6/kernel/sound/core/oss/snd-mixer-oss.ko): Unknown
761symbol in module, or unknown parameter (see dmesg) FATAL: Error inserting
762snd_pcm_oss
763(/lib/modules/2.6.12-gentoo-r6/kernel/sound/core/oss/snd-pcm-oss.ko): Unknown
764symbol in module, or unknown parameter (see dmesg)
765 [ !! ]
766 * Loading: snd-mixer-oss ...
767FATAL: Error inserting snd_mixer_oss
768(/lib/modules/2.6.12-gentoo-r6/kernel/sound/core/oss/snd-mixer-oss.ko): Unknown
769symbol in module, or unknown parameter (see dmesg)
770 [ !! ]
771 * Loading: snd-seq ... [ ok ]
772 * Loading: snd-emu10k1-synth ... [ ok ]
773 * Loading: snd-seq-midi ... [ ok ]
774 * Restoring Mixer Levels ... [ ok ]
775</pre>
776
777<p>
778And when you take a look at <c>dmesg</c> as suggested, you're quite likely to
779see:
780</p>
781
782<pre caption="dmesg output">
783<comment>(Only relevant portions are shown below)</comment>
784# <i>dmesg | less</i>
785ACPI: PCI Interrupt 0000:02:06.0[A] -> Link [APC3] -> GSI 18 (level, low) -> IRQ 209
786snd_mixer_oss: Unknown symbol snd_unregister_oss_device
787snd_mixer_oss: Unknown symbol snd_register_oss_device
788snd_mixer_oss: Unknown symbol snd_mixer_oss_notify_callback
789snd_mixer_oss: Unknown symbol snd_oss_info_register
790snd_pcm_oss: Unknown symbol snd_unregister_oss_device
791snd_pcm_oss: Unknown symbol snd_register_oss_device
792snd_pcm_oss: Unknown symbol snd_mixer_oss_ioctl_card
793snd_pcm_oss: Unknown symbol snd_oss_info_register
794snd_mixer_oss: Unknown symbol snd_unregister_oss_device
795snd_mixer_oss: Unknown symbol snd_register_oss_device
796snd_mixer_oss: Unknown symbol snd_mixer_oss_notify_callback
797snd_mixer_oss: Unknown symbol snd_oss_info_register
798</pre>
799
800<p>
801The above issue is caused when you switch from <c>alsa-driver</c> to in-kernel
802ALSA because when you unmerge <c>alsa-driver</c> the module files are config
803protected and hence get left behind. So, when you switch to in-kernel
804drivers, running <c>modprobe</c> gives you a mix of <c>alsa-driver</c> and
805in-kernel modules thus causing the above errors.
806</p>
807
808<p>
809The solution is quite easy. We just need to manually remove the problem causing
810directory after you unmerge <c>alsa-driver</c>. Be sure to remove the correct
811kernel version and not the current one!
812</p>
813
814<pre caption="Removing the alsa-driver modules">
815# <i>rm -rf /lib/modules/$(uname -r)/alsa-driver</i>
816</pre>
817
818<p>
819Another reason for error messages similar to the ones above could be a file in
820<path>/etc/modules.d</path> supplying a <c>device_mode</c> parameter when it
821isn't required. Confirm that this is indeed the issue and find out which file
822is the culprit.
823</p>
824
825<pre caption="Confirming and searching for device_mode">
826<comment>(Check dmesg to confirm)</comment>
827# <i>dmesg | grep device_mode</i>
828snd: Unknown parameter `device_mode'
829<comment>(Now, to get to the source of the issue)</comment>
830# <i>grep device_mode /etc/modules.d/*</i>
831</pre>
832
833<p>
834Usually it is a file called <path>alsa</path> with the line <c>options snd
835device_mode=0666</c>. Remove this line and restart the alsasound service and
836that should take care of this issue.
837</p>
838
839</body>
840</section>
841</chapter>
842
843<chapter>
844<title>Other things ALSA</title>
845<section id="midi">
846<title>Setting up MIDI support</title>
847<body>
848
849<p>
850First, check to make sure that you enabled the <c>midi</c> USE flag in
851<path>/etc/make.conf</path>.
852</p>
853
854<pre caption="MIDI support in /etc/make.conf">
855USE="midi"
856</pre>
857
858<p>
859If you didn't previously enable <c>midi</c>, go ahead and add it to
860<path>/etc/make.conf</path> now. You will also need to re-emerge any ALSA
861packages that use the <c>midi</c> flag, such as <c>alsa-lib</c>,
862<c>alsa-utils</c>, and <c>alsa-driver</c>.
863</p>
864
865<p>
866If your sound card is one of those that come with on-board MIDI synthesizers
867and you would like to listen to some .mid files, you have to install
868<c>awesfx</c> which is basically a set of utilities for controlling the AWE32
869driver. We need to install it first. If you don't have a hardware synthesizer,
870you can use a virtual one. Please see the section on
871<uri link="#vsynth">Virtual Synthesizers</uri> for more information.
872</p>
873
874<pre caption="Installing awesfx">
875# <i>emerge awesfx</i>
876</pre>
877
167<note> 878<note>
168When you want to install ALSA drivers for more than one soundcard, you could set ALSA_CARDS to a space-separated list 879You will need to copy over SoundFont (SF2) files from your sound card's driver
169of drivers; like this: <c>env ALSA_CARDS='emu10k1 intel8x0 ens1370' emerge alsa-driver</c> 880CD or a Windows installation into <path>/usr/share/sounds/sf2/</path>. For
881example a sound font file for the Creative SBLive! card would be 8MBGMSFX.SF2.
170</note> 882</note>
171 883
172<note>If you want to have OSS compatibility, make sure to emerge <i>alsa-oss</i>, it is the ALSA/OSS compatibility
173wrapper. </note>
174
175</p> 884<p>
885After copying over the Soundfont files, we can then play a midi file as shown.
886You can also add the <c>asfxload</c> command to
887<path>/etc/conf.d/local.start</path>, so that the sound font is loaded
888every time the system starts up.
176<p> 889</p>
177After 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>
185Let's start configuring now to get ALSA working properly.
186We'll need to edit some files, to let our system know about the freshly installed ALSA modules.
187</p>
188<p>
189First file to edit is <path>/etc/modules.d/alsa</path>.
190</p>
191<warn>
192There is no need to edit <path>/etc/modules.conf</path>. Instead, always edit files in <path>/etc/modules.d</path>.
193</warn>
194<p>
195Check the ALSA portion <e>at the bottom of the file</e>.
196By tweaking 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# $Header: /var/cvsroot/gentoo/xml/htdocs/doc/en/alsa-guide.xml,v 1.7 2003/02/09 23:27:14 zhen Exp $
202 890
203# ALSA portion
204alias char-major-116 snd
205<c>options snd major=116 cards_limit=1</c>
206# OSS/Free portion
207alias char-major-14 soundcore
208
209##
210## IMPORTANT:
211</pre>
212</p>
213<p>
214Now 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> 891<note>
232If you have more than one soundcard, adjust the <c>cards_limit</c> value and add more snd-card aliases to the file. 892<path>/mnt</path> paths mentioned in the code listing(s) below will <e>not</e>
233I don't have experience with this, but you can find examples for configurations with two or more soundcards in 893be the same in your machine. They are just an example. Please be careful to
234<uri link="http://www.alsa-project.org/alsa-doc/alsa-howto/c1660.htm">Chapter 6</uri> 894change the path to suit your machine.
235of the <uri link="http://www.alsa-project.org/alsa-doc/alsa-howto/alsa-howto.html">ALSA Howto</uri>.
236</note> 895</note>
237</p> 896
238<p> 897<pre caption="Loading Soundfonts">
239Last thing to do in this file, at the very bottom, check if these lines are there and uncommented: 898<comment>(First, copy the Soundfont)</comment>
240<pre caption="at the very bottom of /etc/modules.d/alsa"> 899# <i>cp /mnt/win2k/Program\ Files/CreativeSBLive2k/SFBank/8MBGMSFX.SF2 /usr/share/sounds/sf2/</i>
241alias /dev/mixer snd-mixer-oss 900<comment>(Or get it from your SoundBlaster CD)</comment>
242alias /dev/dsp snd-pcm-oss 901# <i>cp /mnt/cdrom/AUDIO/ENGLISH/SFBANK/8MBGMSFX.SF2 /usr/share/sounds/sf2/</i>
243alias /dev/midi snd-seq-oss 902<comment>(We load the specific Soundfont)</comment>
244</pre> 903# <i>asfxload /usr/share/sounds/sf2/8MBGMSFX.SF2</i>
245</p>
246<p>
247Now 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> 904</pre>
249# <c>update-modules</c> 905
250</pre>
251</p> 906<p>
252<note> 907You can now play midi files using a program like <c>aplaymidi</c>. Run
253Running <c>update-modules</c> here will insert the data from <path>/etc/modules.d/alsa</path> into <path>/etc/modules.conf</path> 908<c>aplaymidi -l</c> to get a list of available ports and then pick one
254</note> 909to play the file on.
255<p> 910</p>
256You should also verify that /etc/devfsd.conf has the alsa devices and permissions correctly registered. 911
257</p> 912<pre caption="Playing MIDI">
913<comment>(Check open ports)</comment>
914# <i>aplaymidi -l</i>
915 Port Client name Port name
916 64:0 EMU10K1 MPU-401 (UART) EMU10K1 MPU-401 (UART)
917 65:0 Emu10k1 WaveTable Emu10k1 Port 0
918 65:1 Emu10k1 WaveTable Emu10k1 Port 1
919 65:2 Emu10k1 WaveTable Emu10k1 Port 2
920 65:3 Emu10k1 WaveTable Emu10k1 Port 3
921<comment>(Pick a port, and play a mid file)</comment>
922# <i> aplaymidi --port=65:0 /mnt/shyam/music/midi/mi2.mid</i>
258<pre> 923</pre>
259# nano -w /etc/devfsd.conf 924
260</pre>
261<pre>
262# ALSA/OSS stuff
263# Comment/change these if you want to change the permissions on
264# the audio devices
265LOOKUP snd MODLOAD ACTION snd
266LOOKUP dsp MODLOAD
267LOOKUP mixer MODLOAD
268LOOKUP midi MODLOAD
269REGISTER sound/.* PERMISSIONS root.audio 660
270REGISTER snd/.* PERMISSIONS root.audio 660
271</pre>
272<note>
273Notice 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> 925</body>
276</section>
277</chapter>
278<chapter>
279<title>Starting ALSA</title>
280<section> 926</section>
281 <title>Adding alsasound to a runlevel</title> 927<section id="vsynth">
282<body> 928<title>Virtual Synthesizers</title>
283<p>
284First 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> 929<body>
293</section> 930
931<p>
932If your sound card lacks a hardware synthesizer, you could use a virtual one
933like <c>timidity++</c>. Installation is a breeze.
934</p>
935
936<pre caption="Installing timidity++">
937# <i>emerge timidity++</i>
938</pre>
939
940<p>
941For timidity to play sounds, it needs a sound font. Fortunately, the ebuild will
942install some sound font packages for you. There are a few other font packages
943available in Portage, such as <c>timidity-freepats</c> and
944<c>timidity-eawpatches</c>. You can have multiple sound font configurations
945installed, and you can place your own in <path>/usr/share/timidity/</path>. To
946switch between different timidity configurations, you should use
947<c>eselect</c>.
948</p>
949
950<pre caption="Changing configurations">
951# <i>eselect timidity list</i>
952# <i>eselect timidity set eawpatches</i>
953</pre>
954
955<p>
956Don't forget to add <c>timidity</c> to the default runlevel.
957</p>
958
959<pre caption="Adding timidity to the default runlevel">
960# <i>rc-update add timidity default</i>
961# <i>/etc/init.d/timidity start</i>
962</pre>
963
964<p>
965You can now try out <uri link="#doc_chap4_pre3">Playing MIDI</uri> files.
966</p>
967
968</body>
294<section> 969</section>
295 <title>Running and unmuting</title>
296<body>
297<p>
298Since 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>
304ALSA is running now. If everything is ok, you should be able to see the ALSA modules loaded when running <c>lsmod</c>.
305However, 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>
313You 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>
323If 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>
332We check to see if sound is working by using the aplay (alsa play) command. If you hear a pop, then sound is indeed working.
333Then, adjust the volume settings to your liking; the ncurses-based <c>alsamixer</c> is a great way to get them "just so".
334<p>
335You may want to emerge <c>alsa-xmms</c> as that will provide ALSA support for XMMS.
336</p>
337When you reboot your system, the <e>alsasound</e> init script will properly save and restore your volume settings.
338</body>
339</section> 970<section>
340</chapter> 971<title>Tools and Firmware</title>
341<chapter> 972<body>
342<title>Final Notes</title> 973
974<p>
975Some specific sound cards can benefit from certain tools provided by the
976<c>alsa-tools</c> and <c>alsa-firmware</c> packages. You may install either with
977a simple <c>emerge</c>.
978</p>
979
980<pre caption="Installing ALSA Tools">
981# <i>emerge alsa-tools</i>
982</pre>
983
984</body>
343<section> 985</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
348have 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">
351emerge alsa-driver
352</pre>
353</body>
354</section> 986<section>
987<title>Multiple sound cards</title>
988<body>
989
990<p>
991You can more than one sound card in your system simultaneously, provided that
992you have built ALSA as modules in your kernel (or have installed
993<c>alsa-driver</c> instead). You just need to specify which should be started
994first in <path>/etc/modules.d/alsa</path>. Your cards are identified by their
995driver names inside this file. 0 is the first card, 1 is the second, and so on.
996Here's an example for a system with two sound cards.
997</p>
998
999<pre caption="Two sound cards in /etc/modules.d/alsa">
1000options snd-emu10k1 index=0
1001options snd-via82xx index=1
1002</pre>
1003
1004<p>
1005Or, if you have two cards that use the same driver, you specify them on the same
1006line, using comma-separated numbers. Here's an example for a system with three
1007sound cards, two of which are the same Intel High Definition Audio card.
1008</p>
1009
1010<pre caption="Multiple sound cards in /etc/modules.d/alsa">
1011options snd-ymfpci index=0
1012options snd-hda-intel index=1,2
1013</pre>
1014
1015</body>
355<section> 1016</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
359load 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.
361Check the <uri link="http://www.djcj.org/LAU/guide/alsbook/faq1.html">this FAQ</uri> for more info.</p>
362</body>
363</section> 1017<section>
1018<title>Plugins</title>
1019<body>
1020
1021<p>
1022You may want to install some plugins for extra functionality.
1023<c>alsa-plugins</c> is a collection of useful plugins, which include: PulseAudio
1024output, a sample rate converter, jack (a low-latency audio server), and an
1025encoder that lets you output 6-channel audio through digital S/PDIF connections
1026(both optical and coaxial). You can choose which of its plugins you want
1027installed by adding their USE flags to <path>/etc/portage/package.use</path>.
1028</p>
1029
1030<pre caption="Installing alsa-plugins">
1031# <i>emerge -avt alsa-plugins</i>
1032</pre>
1033
1034</body>
364<section> 1035</section>
365 <title>More links..</title> 1036<section>
1037<title>A big thank you to...</title>
1038<body>
1039
1040<p>
1041Everyone who contributed to the earlier version of the Gentoo ALSA Guide:
1042Vincent Verleye, Grant Goodyear, Arcady Genkin, Jeremy Huddleston,
1043John P. Davis, Sven Vermeulen, Benny Chuang, Tiemo Kieft and Erwin.
1044</p>
1045
366<body> 1046</body>
367<p> 1047</section>
368You could check these for additional info: 1048<section>
369</p> 1049<title>References</title>
370<p> 1050<body>
1051
371<ul> 1052<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> 1053 <li><uri link="http://www.alsa-project.org/">The ALSA Project</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> 1054 <li><uri link="http://linux-sound.org">Linux Sound/MIDI Software</uri></li>
378</ul> 1055</ul>
379</p> 1056
380</body> 1057</body>
381</section> 1058</section>
382</chapter> 1059</chapter>
383</guide> 1060</guide>

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