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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 1.75 2007/03/10 13:02:28 jkt 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<author title="Author"><mail link="g2boojum@gentoo.org"> 12<author title="Author">
10 Grant Goodyear</mail> 13 <mail link="nightmorph@gentoo.org">Joshua Saddler</mail>
11</author> 14</author>
12<author title="Author"><mail link="agenkin@gentoo.org"> 15<author title="Contributor">
13 Arcady Genkin</mail> 16 <mail link="flameeyes@gentoo.org">Diego Pettenò</mail>
14</author> 17</author>
15<author title="Editor"><mail link="zhen@gentoo.org">
16 John P. Davis</mail>
17</author>
18<author title="Editor"><mail link="swift@gentoo.org">
19 Sven Vermeulen</mail>
20</author>
21<author title="Editor"><mail link="bennyc@gentoo.org">
22 Benny Chuang</mail>
23</author>
24<author title="Editor"><mail link="blubber@gentoo.org">
25 Tiemo Kieft</mail>
26</author>
27 18
19<abstract>
20This document helps a user setup ALSA on Gentoo Linux.
21</abstract>
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 -->
28<license/> 25<license/>
29 26
30<abstract>
31This guide will show you how to set up the Advanced Linux Sound Architecture (ALSA) on Gentoo Linux.
32In addition to the Gentoo Linux Desktop Configuration Guide, this guide is supposed to give you more information on this subject. </abstract>
33
34<version>1.3.3</version> 27<version>2.18</version>
35<date>October 9, 2003</date> 28<date>2007-02-17</date>
36 29
37<chapter> 30<chapter>
38<title>Introduction</title> 31<title>Introduction</title>
39<section> 32<section>
40 <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
41<body> 52</body>
42<p> 53</section>
43The Advanced Linux Sound Architecture (ALSA) is a project to improve the Linux sound subsystem by rewriting 54<section>
44large chunks of it. 55<title>ALSA on Gentoo</title>
45It 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
46</p> 58<p>
47 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.
48<p> 63</p>
49ALSA 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
50</p> 80<p>
51 81The two options are :
52<p> 82</p>
53Quoted from <uri>http://www.alsa-project.org</uri>, ALSA has the following features: 83
54<ul><li> Efficient support for all types of audio interfaces, from consumer soundcards to professional multichannel audio interfaces.</li> 84<ol>
55 <li> Fully modularized sound drivers.</li> 85 <li>Use ALSA provided by your kernel.</li>
56 <li> SMP and thread-safe design.</li> 86 <li>Use Gentoo's <c>media-sound/alsa-driver</c> package.</li>
57 <li> User space library (alsa-lib) to simplify application programming and provide higher level functionality.</li> 87</ol>
58 <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>
59</ul> 199</ul>
60There's lots more to ALSA however, like support for Full Duplex playback and recording, multiple soundcard support, 200
61hardware 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
62</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
63</body> 232</body>
64</section>
65<section> 233</section>
66 <title>Why use ALSA?</title> 234<section id="kernel">
67<body> 235<title>Using ALSA provided by your Kernel</title>
68<p>
69If your soundcard is supported by the Linux kernel sound system or the commercial OSS/4Front sound driver system,
70which can be found in all 2.4.x Linux kernels, you could just aswell build <e>those modules</e> for use with your soundcard.
71If 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>
74However, those OSS/4Front drivers have some limitations -- being commercial is one.
75ALSA is an attempt to go beyond these limitations and to do so in an open source fashion.
76ALSA is a fully GPL and LGPL'ed sound driver system, that provides a professional quality system for recording, playback,
77and MIDI sequencing.
78</p>
79</body> 236<body>
80</section> 237
238<p>
239If you're a person who likes to keep things simple like I do, then this is
240the way to go.
241</p>
242
243<note>
244Since the 2005.0 release, Gentoo Linux uses 2.6 as the default kernel. Unless
245you are specifically using the 2.4 profile, <c>gentoo-sources</c> will be a
2462.6 kernel on <e>most</e> architectures. Please check that your kernel is a
2472.6 series kernel. This method will <e>not</e> work on a 2.4 kernel.
248</note>
249
250<p>
251Let us now configure the kernel to enable ALSA.
252</p>
253
254<impo>
255<c>genkernel</c> users should now run <c>genkernel --menuconfig all</c> and
256then follow the instructions in <uri link="#doc_chap2_pre3">Kernel Options for
257ALSA</uri>.
258</impo>
259
260<pre caption="Heading over to the source">
261# <i>cd /usr/src/linux</i>
262# <i>make menuconfig</i>
263</pre>
264
265<note>
266The above example assumes that <path>/usr/src/linux</path> symlink points to
267the kernel sources you want to use. Please ensure the same before proceeding.
268</note>
269
270<p>
271Now we will look at some of the options we will have to enable in the 2.6
272kernel to ensure proper ALSA support for our sound card.
273</p>
274
275<p>
276Please note that for ease of use, all examples show ALSA built as modules. It
277is advisable to follow the same as it then allows the use of <c>alsaconf</c>
278which is a boon when you want to configure your card. Please do <e>not</e> skip
279the <uri link="#alsa-config">Configuration</uri> section of this document. If
280you still like to have options built-in, ensure that you make changes to your
281config accordingly.
282</p>
283
284<pre caption="Kernel Options for ALSA">
285Device Drivers ---&gt;
286 Sound ---&gt;
287
288<comment>(This needs to be enabled)</comment>
289&lt;M&gt; Sound card support
290
291<comment>(Make sure OSS is disabled)</comment>
292Open Sound System ---&gt;
293 &lt; &gt; Open Sound System (DEPRECATED)
294
295<comment>(Move one step back and enter ALSA)</comment>
296Advanced Linux Sound Architecture ---&gt;
297 &lt;M&gt; Advanced Linux Sound Architecture
298 <comment>(Select this if you want MIDI sequencing and routing)</comment>
299 &lt;M&gt; Sequencer support
300 <comment>(Old style /dev/mixer* and /dev/dsp* support. Recommended.)</comment>
301 &lt;M&gt; OSS Mixer API
302 &lt;M&gt; OSS PCM (digital audio) API
303
304<comment>(You now have a choice of devices to enable support for. Generally,
305you will have one type of device and not more. If you have more than one
306sound card, please enable them all here.)</comment>
307
308<comment>(Mostly for testing and development purposes, not needed for normal
309users unless you know what you are doing.)</comment>
310Generic devices ---&gt;
311
312<comment>(For ISA Sound cards)</comment>
313ISA devices ---&gt;
314<comment>(IF you had the Gravis, you would select this option)</comment>
315 &lt;M&gt; Gravis UltraSound Extreme
316
317<comment>(Move one level back and into PCI devices. Most sound cards today are
318PCI devices)</comment>
319PCI devices ---&gt;
320 <comment>(We now select the emu10k1 driver for our card)</comment>
321 &lt;M&gt; Emu10k1 (SB Live!, Audigy, E-mu APS)
322 <comment>(Or an Intel card would be)</comment>
323 &lt;M&gt; Intel/SiS/nVidia/AMD/ALi AC97 Controller
324 <comment>(Or if you have a VIA Card)</comment>
325 &lt;M&gt; VIA 82C686A/B, 8233/8235 AC97 Controller
326
327<comment>(Move one level back and select in case you have an USB sound card)</comment>
328USB Devices ---&gt;
329</pre>
330
331<p>
332Now that your options are set, you can (re)compile the kernel and ALSA support
333for your card should be functional once you reboot into the new kernel. Don't
334forget to update your GRUB configuration to use the newly built kernel.
335You can now proceed to <uri link="#alsa-utilities">ALSA Utilities</uri> and
336see if everything is working as it should.
337</p>
338
339</body>
81<section> 340</section>
82 <title>What cards does ALSA support?</title> 341<section id="alsa-driver">
342<title>Using the ALSA Driver package</title>
83<body> 343<body>
84<p> 344
85ALSA tries to support as many (new) cards as possible by providing open-source drivers.
86However, some vendors may provide binary-only packages.
87</p> 345<p>
88<p>To know if your card is supported, you can find a Soundcard Matrix of supported and not-supported cards here: 346So you've decided to go the <c>alsa-driver</c> way. Let's get started then.
89<uri>http://www.alsa-project.org/alsa-doc/</uri>. 347There are a few minor things to be done to ensure only the drivers for your
348sound card are compiled. Although this is not really necessary, it cuts down
349on the unnecessary drivers that will be compiled otherwise.
350</p>
351
90</p> 352<p>
353If you don't have an idea of what drivers your sound card might need, please
354take a look at the <uri link="#lspci">lspci</uri> section of this guide. Once
355you have your driver name (<c>emu10k1</c> in our example), edit
356<path>/etc/make.conf</path> and add a variable, <c>ALSA_CARDS</c>.
357</p>
358
359<pre caption="Adding ALSA_CARDS to make.conf">
360<comment>(For one sound card)</comment>
361ALSA_CARDS="emu10k1"
362<comment>(For more than one, separate names with spaces)</comment>
363ALSA_CARDS="emu10k1 via82xx"
364</pre>
365
366<p>
367If you have compiled your kernel and want to use <c>alsa-driver</c>, please
368ensure the following before proceeding, else <c>alsa-driver</c> is likely to
369fail. The next code listing gives you one way of performing the checks.
370</p>
371
372<note>
373<c>genkernel</c> users can proceed with <uri link="#doc_chap2_pre6">Installing
374alsa-driver</uri> as their configuration is in sync with the one shown below by
375default.
376</note>
377
378<ol>
379 <li>
380 <c>CONFIG_SOUND</c> is set. (Basic Sound support enabled)
381 </li>
382 <li>
383 <c>CONFIG_SOUND_PRIME</c> is not set. (In-built OSS support disabled)
384 </li>
385 <li>
386 <c>CONFIG_SND</c> is not set. (In-built ALSA support disabled)
387 </li>
388 <li>
389 <path>/usr/src/linux</path> points to the kernel you want ALSA working on.
390 </li>
391</ol>
392
393<pre caption=".config checks">
394<comment>(Assuming the linux symlink points to the correct kernel)</comment>
395# <i>cd /usr/src/linux</i>
396# <i>grep SOUND .config</i>
397<comment>(1. is true)</comment>
398CONFIG_SOUND=y
399<comment>(2. is true)</comment>
400CONFIG_SOUND_PRIME is not set
401# <i>grep SND .config</i>
402<comment>(and 3. is true)</comment>
403CONFIG_SND is not set
404</pre>
405
406<p>
407Now all you have to do is type the magic words... and no, it's not abracadabra.
408</p>
409
410<pre caption="Installing alsa-driver">
411# <i>emerge alsa-driver</i>
412</pre>
413
414<impo>
415Please note that you will have to run <c>emerge alsa-driver</c> after every
416kernel (re)compile, as the earlier drivers are deleted. To make this task
417easier, you may want to emerge the <c>module-rebuild</c> package, which will
418keep track of module packages and rebuild them for you. First run
419<c>module-rebuild populate</c> to create the list, and then after every kernel
420(re)compile, you just run <c>module-rebuild rebuild</c>, and your external
421modules will be rebuilt.
422</impo>
423
91</body> 424</body>
92</section> 425</section>
93</chapter> 426</chapter>
94 427
95<chapter> 428<chapter>
96<title>Installation</title> 429<title>Configuring/Testing ALSA</title>
97<section> 430<section id="alsa-utilities">
98<title>Gentoo USE flags</title> 431<title>ALSA Utilities</title>
99<body>
100
101<p>
102To compile programs with ALSA-support, be sure to add <e>alsa</e> to
103your USE-variable. However, several tools don't support alsa yet, and
104require OSS. ALSA provides OSS-emulation if you define <e>oss</e> in your
105USE-variable before you start.
106</p>
107
108</body> 432<body>
109</section>
110 433
111<section>
112 <title>Kernel modules</title>
113<body>
114<p>
115Since 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</p> 434<p>
435<c>alsa-utils</c> forms an integral part of ALSA as it has a truckload of
436programs that are highly useful, including the ALSA Initscripts. Hence we
437strongly recommend that you install <c>alsa-utils</c>
117<p> 438</p>
118First we'll make sure that our kernel configuration is ready for use with ALSA. 439
119All you need in your kernel configuration is having Sound Card Support set to be built as a module (M). 440<pre caption="Install alsa-utils">
120This will build <c>soundcore.o</c>. 441# <i>emerge alsa-utils</i>
121</p> 442</pre>
122<p> 443
123<note> 444<note>
124Possibly, this will also work when you built Sound Card Support in the kernel (Y) instead of building it as a module (M). 445If you activated ALSA in your <uri link="#kernel">kernel</uri> <e>and</e> did
125However, the official ALSA documentation suggests building it as a module, since ALSA will try loading it. 446not compile ALSA as modules, please proceed to the
447<uri link="#initscript">ALSA Initscript</uri> section. The rest of you need
448to configure ALSA. This is made very easy by the existence of the
449<c>alsaconf</c> tool provided by <c>alsa-utils</c>.
126</note> 450</note>
451
452</body>
453</section>
454<section id="alsa-config">
455<title>Configuration</title>
456<body>
457
127</p> 458<p>
128<p>If you already have a working kernel configuration, make sure you remove all sound drivers (except for Sound Card Support). 459Recent versions of <c>udev</c> (<c>>=udev-103</c>) provide some degree of
129If you wish to do this without having to reboot, you could do like this: 460kernel-level autoconfiguration of your sound card. If possible, try to rely on
461just letting your kernel automatically setup your sound card for you. Otherwise,
462use <c>alsaconf</c> to configure your card, as shown below.
463</p>
464
465<note>
466Please shut down any programs that <e>might</e> access the sound card while
467running <c>alsaconf</c>.
468</note>
469
130</p> 470<p>
471Another way to configure your sound card is to run <c>alsaconf</c>. Just type
472<c>alsaconf</c> in a shell as root.
473</p>
474
475<pre caption="Invoking alsaconf">
476# <i>alsaconf</i>
131<pre> 477</pre>
132# <i>cd /usr/src/linux</i> 478
133# <i>cp .config ~/</i>
134# <i>make mrproper</i>
135# <i>cp ~/.config .</i>
136# <i>make menuconfig</i>
137</pre>
138<p>
139Now select <e>Sound Card Support</e> as Module (M) and deselect all other sound drivers.
140Exit and say Y to save your kernel configuration.
141After that, build the modules:
142</p> 479<p>
480You will now see a neat menu guided interface that will automatically probe
481your devices and try to find out your sound card. You will be asked to pick
482your sound card from a list. Once that's done, it will ask you permission to
483automatically make required changes to <path>/etc/modules.d/alsa</path>.
484It will then adjust your volume settings to optimum levels, run
485<c>modules-update</c> and start the <path>/etc/init.d/alsasound</path> service.
486Once <c>alsaconf</c> exits, you can proceed with setting up the ALSA
487initscript.
488</p>
489
490</body>
491</section>
492<section id="initscript">
493<title>ALSA Initscript</title>
494<body>
495
496<p>
497We're now almost all setup. Whichever method you chose to install ALSA, you'll
498need to have something load your modules or initialize ALSA and restore your
499volume settings when your system comes up. The ALSA Initscript handles all of
500this for you and is called <c>alsasound</c>. Add it to the boot runlevel.
501</p>
502
503<pre caption="Adding ALSA to the boot runlevel">
504# <i>rc-update add alsasound boot</i>
505 * alsasound added to runlevel boot
506 * rc-update complete.
143<pre> 507</pre>
144# <i>make dep clean</i> 508
145# <i>make modules modules_install</i>
146</pre>
147<p>
148Before installing your new modules, this last line will delete all your previous modules,
149even the ones from a previous ALSA installation.
150</p> 509<p>
510Next, just check the <path>/etc/conf.d/alsasound</path> file and ensure that
511SAVE_ON_STOP variable is set to yes. This saves your sound settings when you
512shutdown your system.
151<p> 513</p>
514
515</body>
516</section>
517<section>
518<title>Audio Group</title>
519<body>
520
521<p>
522Before we move on to testing, there's one last <e>important</e> thing that needs
523to be setup. Rule of thumb in a *nix OS : Do not run as root unless needed.
524This applies here as well ;) How? Well, most of the times you should be logged
525in as a user and would like to listen to music or access your soundcard. For
526that to happen, you need to be in the "audio" group. At this point, we'll add
527users to the audio group, so that they won't have any issues when they want to
528access sound devices. We'll use <c>gpasswd</c> here and you need to be logged in
529as root for this to work.
530</p>
531
532<pre caption="Adding users to the audio group">
533<comment>(Substitute &lt;username&gt; with your user)</comment>
534# <i>gpasswd -a &lt;username&gt; audio </i>
535Adding user &lt;username&gt; to group audio
536</pre>
537
538</body>
539</section>
540<section>
541<title>Volume Check!</title>
542<body>
543
544<p>
545We've completed all the setups and prerequisites, so let's fire up ALSA. If
546you ran <c>alsaconf</c>, you can skip this step, since <c>alsaconf</c> already
547does this for you.
548</p>
549
550<pre caption="Start the service">
551# <i>/etc/init.d/alsasound start</i>
552</pre>
553
554<p>
555Now that the required things have been taken care of, we need to check up on
556the volume as in certain cases, it is muted. We use <c>alsamixer</c> for this
557purpose.
558</p>
559
560<pre caption="Starting alsamixer">
561<comment>(Opens up a console program. Only required settings are shown)</comment>
562# <i>alsamixer</i>
563</pre>
564
152<impo> 565<impo>
153This means, whenever you recompile your kernel later on, you MUST recompile <c>alsa-driver</c>. 566If you have issues starting up <c>alsamixer</c> and get errors such as
567alsamixer: function snd_ctl_open failed for default: No such file or directory,
568this is usually an issue with udev setting up the devices. Run <c>killall
569udevd; udevstart</c> to reload <path>/dev</path> entries and fire up
570<c>alsamixer</c>. It should solve the issue.
154</impo> 571</impo>
572
155</p> 573<p>
574This is how the ALSA Mixer <e>might</e> look the first time you open it. Pay
575attention to the Master and PCM channels which both have an MM below them.
576That means they are muted. If you try to play anything with <c>alsamixer</c>
577in this state, you will not hear anything on your speakers.
156<p> 578</p>
157<note>However, there's no need to reinstall <c>nvidia-kernel</c>, the Nvidia drivers are in a separate directory 579
158in <path>/lib/modules/*/video</path> and won't get deleted by a <c>make modules modules_install</c> 580<figure link="/images/docs/alsa-mixermuted.png" short="AlsaMixer Muted" caption="The Alsa Mixer Main Window, Muted"/>
581
582<p>
583Now, we shall unmute the channels, and set volume levels as needed.
584</p>
585
586<warn>
587Both Master <e>and</e> PCM need to be unmuted and set to audible volume levels
588if you want to hear some output on your speakers.
589</warn>
590
591<ul>
592 <li>
593 To move between channels, use your left and right arrow keys. (&lt;-
594 &amp; -&gt;)
595 </li>
596 <li>
597 To toggle mute, move to the specific channel, for example Master and press
598 the <e>m</e> key on the keyboard.
599 </li>
600 <li>
601 To increase and decrease the volume levels, use the up and down arrow keys
602 respectively.
603 </li>
604</ul>
605
606<note>
607Be careful when setting your Bass and Treble values. 50 is usually a good
608number for both. Extremely high values of Bass may cause <e>jarring</e>
609on speakers that are not designed to handle them.
159</note> 610</note>
611
160</p> 612<p>
161</body> 613After you're all done, your ALSA Mixer should look similar to the one below.
162</section> 614Note the 00 instead of the MM and also the volume levels for some optimum
615settings.
616</p>
163 617
618<figure link="/images/docs/alsa-mixerunmuted.png" short="AlsaMixer Unmuted" caption="Alsa Mixer ready to roll"/>
619
620</body>
164<section> 621</section>
165 <title>ALSA modules</title> 622<section>
623<title>Sound Check!</title>
624<body>
625
626<p>
627Finally. Some music. If everything above is perfect, you should now be able to
628listen to some good music. A quick way to test is to use a command line tool
629like <c>media-sound/madplay</c>. You could also use something more well known
630like <c>mpg123</c>. If you are an ogg fan, you could use <c>ogg123</c> provided
631by <c>media-sound/vorbis-tools</c>. Use any player you are comfortable with. As
632always, <c>emerge</c> what you need.
633</p>
634
635<pre caption="Getting the software">
636<comment>(Install the applications you want)</comment>
637# <i>emerge madplay mpg123</i>
638<comment>(To play .ogg files)</comment>
639# <i>emerge vorbis-tools</i>
640</pre>
641
642<p>
643And then play your favorite sound track...
644</p>
645
646<pre caption="Playing Music">
647# <i>madplay -v /mnt/shyam/Music/Paul\ Oakenfold\ -\ Dread\ Rock.mp3</i>
648MPEG Audio Decoder 0.15.2 (beta) - Copyright (C) 2000-2004 Robert Leslie et al.
649 Title: Dread Rock
650 Artist: Paul Oakenfold
651 Album: Matrix Reloaded
652 Year: 2003
653 Genre: Soundtrack
654 Soundtrack
655 00:04:19 Layer III, 160 kbps, 44100 Hz, joint stereo (MS), no CRC
656
657# <i>ogg123 Paul\ Oakenfold\ -\ Dread\ Rock.ogg</i>
658Audio Device: Advanced Linux Sound Architecture (ALSA) output
659
660Playing: Paul Oakenfold - Dread Rock.ogg
661Ogg Vorbis stream: 2 channel, 44100 Hz
662Genre: Soundtrack
663Transcoded: mp3;160
664Title: Dread Rock
665Artist: Paul Oakenfold
666Date: 2003
667Album: Matrix Reloaded
668Time: 00:11.31 [04:28.75] of 04:40.06 (200.6 kbps) Output Buffer 96.9%
669</pre>
670
166<body> 671</body>
672</section>
673<section>
674<title>ALSA and USE</title>
675<body>
167 676
168<p>
169Now it's time to install the ALSA drivers for your soundcard(s). If your soundcard is PCI, you can find out the name
170and type of your soundcard by looking at the output of /proc/pci.
171</p> 677<p>
678You can now add the <c>alsa</c> use flag to <path>/etc/make.conf</path> to
679ensure that your applications that support ALSA get built with it. Some
680architectures like x86 and amd64 have the flag enabled by default.
681</p>
682
683</body>
684</section>
685<section>
686<title>Issues?</title>
687<body>
688
689<p>
690If for some reason you're unable to hear sound, the first thing to do would
691be to check your <uri link="#doc_chap3_pre6">alsamixer</uri> settings. 80% of
692the issues lie with muted channels or low volume. Also check your Window
693Manager's sound applet and verify that volumes are set to audible levels.
694</p>
695
696<p>
697<path>/proc</path> is your friend. And in this case, <path>/proc/asound</path>
698is your best friend. We shall just take a short look at how much info is made
699available to us there.
700</p>
701
702<pre caption="Fun with /proc/asound">
703<comment>(First and foremost, if /proc/asound/cards shows your card, ALSA has
704picked up your sound card fine.)</comment>
705# <i>cat /proc/asound/cards</i>
7060 [Live ]: EMU10K1 - Sound Blaster Live!
707 Sound Blaster Live! (rev.6, serial:0x80271102) at 0xb800, irq 11
708
709<comment>(If you run ALSA off the kernel like I do and wonder how far behind
710you are from alsa-driver, this displays current running ALSA version)</comment>
711# <i>cat /proc/asound/version</i>
712Advanced Linux Sound Architecture Driver Version 1.0.8 (Thu Jan 13 09:39:32 2005 UTC).
713
714<comment>(ALSA OSS emulation details)</comment>
715# <i>cat /proc/asound/oss/sndstat</i>
716Sound Driver:3.8.1a-980706 (ALSA v1.0.8 emulation code)
717Kernel: Linux airwolf.zion 2.6.11ac1 #2 Wed May 4 00:35:08 IST 2005 i686
718Config options: 0
719
720Installed drivers:
721Type 10: ALSA emulation
722
723Card config:
724Sound Blaster Live! (rev.6, serial:0x80271102) at 0xb800, irq 11
725
726Audio devices:
7270: EMU10K1 (DUPLEX)
728
729Synth devices: NOT ENABLED IN CONFIG
730
731Midi devices:
7320: EMU10K1 MPU-401 (UART)
733
734Timers:
7357: system timer
736
737Mixers:
7380: SigmaTel STAC9721/23
172<pre> 739</pre>
173# <i>grep audio /proc/pci</i>
174</pre>
175 740
176
177<p>
178<warn>
179If you had a previous sound setup and there are still non-ALSA sound modules loaded, unload them <e>now</e>.
180Check with <c>lsmod</c> and use <c>rmmod</c> to unload all sound-related modules on your system.
181</warn>
182</p> 741<p>
183 742The other most common issue users face is the dreaded "Unknown symbol in module"
743error. An example of the same is shown below.
184<p> 744</p>
185We 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>
188However, to save some time, lookup the <e>Module Name</e> of your soundcard(s) on the
189<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.
190Mine is <c>snd-emu10k1</c>, since I have an SBlive! soundcard, with the <e>EMU10K1</e> chipset.
191We'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</p>
193 745
746<pre caption="Unknown Symbol in module error">
747# <i>/etc/init.d/alsasound start</i>
748 * Loading ALSA modules ...
749 * Loading: snd-card-0 ... [ ok ]
750 * Loading: snd-pcm-oss ...
751WARNING: Error inserting snd_mixer_oss
752(/lib/modules/2.6.12-gentoo-r6/kernel/sound/core/oss/snd-mixer-oss.ko): Unknown
753symbol in module, or unknown parameter (see dmesg) FATAL: Error inserting
754snd_pcm_oss
755(/lib/modules/2.6.12-gentoo-r6/kernel/sound/core/oss/snd-pcm-oss.ko): Unknown
756symbol in module, or unknown parameter (see dmesg)
757 [ !! ]
758 * Loading: snd-mixer-oss ...
759FATAL: 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)
762 [ !! ]
763 * Loading: snd-seq ... [ ok ]
764 * Loading: snd-emu10k1-synth ... [ ok ]
765 * Loading: snd-seq-midi ... [ ok ]
766 * Restoring Mixer Levels ... [ ok ]
194<pre> 767</pre>
195# <i>env ALSA_CARDS='emu10k1' emerge alsa-driver</i> 768
769<p>
770And when you take a look at <c>dmesg</c> as suggested, you're quite likely to
771see:
196</pre> 772</p>
773
774<pre caption="dmesg output">
775<comment>(Only relevant portions are shown below)</comment>
776# <i>dmesg | less</i>
777ACPI: PCI Interrupt 0000:02:06.0[A] -> Link [APC3] -> GSI 18 (level, low) -> IRQ 209
778snd_mixer_oss: Unknown symbol snd_unregister_oss_device
779snd_mixer_oss: Unknown symbol snd_register_oss_device
780snd_mixer_oss: Unknown symbol snd_mixer_oss_notify_callback
781snd_mixer_oss: Unknown symbol snd_oss_info_register
782snd_pcm_oss: Unknown symbol snd_unregister_oss_device
783snd_pcm_oss: Unknown symbol snd_register_oss_device
784snd_pcm_oss: Unknown symbol snd_mixer_oss_ioctl_card
785snd_pcm_oss: Unknown symbol snd_oss_info_register
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
790</pre>
791
792<p>
793The above issue is caused when you switch from <c>alsa-driver</c> to in-kernel
794ALSA because when you unmerge <c>alsa-driver</c> the module files are config
795protected and hence get left behind. So, when you switch to in-kernel
796drivers, running <c>modprobe</c> gives you a mix of <c>alsa-driver</c> and
797in-kernel modules thus causing the above errors.
798</p>
799
800<p>
801The solution is quite easy. We just need to manually remove the problem causing
802directory after you unmerge <c>alsa-driver</c>. Be sure to remove the correct
803kernel version and not the current one!
804</p>
805
806<pre caption="Removing the alsa-driver modules">
807# <i>rm -rf /lib/modules/$(uname -r)/alsa-driver</i>
808</pre>
809
810<p>
811Another reason for error messages similar to the ones above could be a file in
812<path>/etc/modules.d</path> supplying a <c>device_mode</c> parameter when it
813isn't required. Confirm that this is indeed the issue and find out which file
814is the culprit.
815</p>
816
817<pre caption="Confirming and searching for device_mode">
818<comment>(Check dmesg to confirm)</comment>
819# <i>dmesg | grep device_mode</i>
820snd: Unknown parameter `device_mode'
821<comment>(Now, to get to the source of the issue)</comment>
822# <i>grep device_mode /etc/modules.d/*</i>
823</pre>
824
825<p>
826Usually it is a file called <path>alsa</path> with the line <c>options snd
827device_mode=0666</c>. Remove this line and restart the alsasound service and
828that should take care of this issue.
829</p>
830
831</body>
832</section>
833</chapter>
834
835<chapter>
836<title>Other things ALSA</title>
837<section id="midi">
838<title>Setting up MIDI support</title>
839<body>
840
841<p>
842First, check to make sure that you enabled the <c>midi</c> USE flag in
843<path>/etc/make.conf</path>. If you didn't, go ahead and add it now. You will
844also need to re-emerge any ALSA packages that use the <c>midi</c> flag, such as
845<c>alsa-lib</c>, <c>alsa-utils</c>, and <c>alsa-driver</c>.
846</p>
847
848<p>
849If your sound card is one of those that come with on-board MIDI synthesizers
850and you would like to listen to some .mid files, you have to install
851<c>awesfx</c> which is basically a set of utilities for controlling the AWE32
852driver. We need to install it first. If you don't have a hardware synthesizer,
853you can use a virtual one. Please see the section on
854<uri link="#vsynth">Virtual Synthesizers</uri> for more information.
855</p>
856
857<pre caption="Installing awesfx">
858# <i>emerge awesfx</i>
859</pre>
860
197<note> 861<note>
198You 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>. 862You will need to copy over SoundFont (SF2) files from your sound card's driver
199For example, like this: <c>echo 'ALSA_CARDS="emu10k1"' >> /etc/make.conf</c> 863CD or a Windows installation into <path>/usr/share/sounds/sf2/</path>. For
864example a sound font file for the Creative SBLive! card would be 8MBGMSFX.SF2.
200</note> 865</note>
201 866
867<p>
868After copying over the Soundfont files, we can then play a midi file as shown.
869You can also add the <c>asfxload</c> command to
870<path>/etc/conf.d/local.start</path>, so that the sound font is loaded
871every time the system starts up.
872</p>
873
202<note> 874<note>
203When you want to install ALSA drivers for more than one soundcard, you could set ALSA_CARDS to a space-separated list 875<path>/mnt</path> paths mentioned in the code listing(s) below will <e>not</e>
204of drivers; like this: <c>env ALSA_CARDS='emu10k1 intel8x0 ens1370' emerge alsa-driver</c> 876be the same in your machine. They are just an example. Please be careful to
877change the path to suit your machine.
205</note> 878</note>
206 879
207<note>If you want to have OSS compatibility, make sure to emerge <i>alsa-oss</i>, it is the ALSA/OSS compatibility 880<pre caption="Loading Soundfonts">
208wrapper. </note> 881<comment>(First, copy the Soundfont)</comment>
882# <i>cp /mnt/win2k/Program\ Files/CreativeSBLive2k/SFBank/8MBGMSFX.SF2 /usr/share/sounds/sf2/</i>
883<comment>(Or get it from your SoundBlaster CD)</comment>
884# <i>cp /mnt/cdrom/AUDIO/ENGLISH/SFBANK/8MBGMSFX.SF2 /usr/share/sounds/sf2/</i>
885<comment>(We load the specific Soundfont)</comment>
886# <i>asfxload /usr/share/sounds/sf2/8MBGMSFX.SF2</i>
887</pre>
209 888
210<note>If you plan on recompiling your kernels numerous times, it might
211be adviseable to emerge <c>alsa-driver</c> with <c>--buildpkg</c>. This
212will create a binary package for it. Later, after recompiling your kernel,
213you can just do <c>emerge --usepkg alsa-driver</c> which will install the
214binary package instead of recompiling it completely.</note>
215
216<p>
217After this, the ALSA modules should be installed on your system.
218</p> 889<p>
890You can now play midi files using a program like <c>aplaymidi</c>. Run
891<c>aplaymidi -l</c> to get a list of available ports and then pick one
892to play the file on.
893</p>
894
895<pre caption="Playing MIDI">
896<comment>(Check open ports)</comment>
897# <i>aplaymidi -l</i>
898 Port Client name Port name
899 64:0 EMU10K1 MPU-401 (UART) EMU10K1 MPU-401 (UART)
900 65:0 Emu10k1 WaveTable Emu10k1 Port 0
901 65:1 Emu10k1 WaveTable Emu10k1 Port 1
902 65:2 Emu10k1 WaveTable Emu10k1 Port 2
903 65:3 Emu10k1 WaveTable Emu10k1 Port 3
904<comment>(Pick a port, and play a mid file)</comment>
905# <i> aplaymidi --port=65:0 /mnt/shyam/music/midi/mi2.mid</i>
906</pre>
907
219</body> 908</body>
220</section>
221<section> 909</section>
222 <title>Configuration of ALSA</title> 910<section id="vsynth">
223<body> 911<title>Virtual Synthesizers</title>
224<p>
225Let's start configuring now to get ALSA working properly.
226We'll need to edit some files, to let our system know about the freshly installed ALSA modules.
227</p>
228
229<p>
230First, 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>
238Hereafter, we need to edit <path>/etc/modules.d/alsa</path>.
239</p>
240<warn>
241There is no need to edit <path>/etc/modules.conf</path>. Instead, always edit files in <path>/etc/modules.d</path>.
242</warn>
243<p>
244Check the ALSA portion <e>at the bottom of the file</e>.
245By tweaking this line you can specify the max number of soundcards you have (generally, just one).
246</p>
247<pre caption="At the bottom of /etc/modules.d/alsa">
248<comment>Set this to the correct number of cards.</comment>
249options snd cards_limit=1
250</pre>
251<p>
252Now we'll specify the sounddriver(s) ALSA should use. In the same file, edit like this:
253</p>
254<pre caption="In /etc/modules.d/alsa">
255## and then run `modules-update' command.
256## Read alsa-driver's INSTALL file in /usr/share/doc for more info.
257##
258## ALSA portion
259alias snd-card-0 snd-emu10k1
260<comment>## If you have more than one, add:</comment>
261## alias snd-card-1 snd-intel8x0
262## alias snd-card-2 snd-ens1370
263## OSS/Free portion
264## alias sound-slot-0 snd-card-0
265## alias sound-slot-1 snd-card-1
266##
267</pre>
268<note>
269If you have more than one soundcard, adjust the <c>cards_limit</c> value and add more snd-card aliases to the file.
270I 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>
272of the <uri link="http://www.alsa-project.org/alsa-doc/alsa-howto/alsa-howto.html">ALSA Howto</uri>.
273</note>
274<p>
275Last thing to do in this file, almost at the end, check if these lines are there and uncommented:
276</p>
277<pre caption="Near the end of /etc/modules.d/alsa">
278alias /dev/mixer snd-mixer-oss
279alias /dev/dsp snd-pcm-oss
280alias /dev/midi snd-seq-oss
281</pre>
282<p>
283Now double-check the file <path>/etc/modules.d/alsa</path> and when you're sure everyting is ok, run <c>modules-update</c>.
284<pre>
285# <i>modules-update</i>
286</pre>
287</p>
288<note>
289Running <c>modules-update</c> here will insert the data from <path>/etc/modules.d/alsa</path> into <path>/etc/modules.conf</path>
290</note>
291<p>
292You should also verify that /etc/devfsd.conf has the alsa devices and permissions correctly registered.
293</p>
294<pre caption="/etc/devfsd.conf">
295# ALSA/OSS stuff
296# Comment/change these if you want to change the permissions on
297# the audio devices
298LOOKUP snd MODLOAD ACTION snd
299LOOKUP dsp MODLOAD
300LOOKUP mixer MODLOAD
301LOOKUP midi MODLOAD
302REGISTER sound/.* PERMISSIONS root.audio 660
303REGISTER snd/.* PERMISSIONS root.audio 660
304</pre>
305<note>
306Notice 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> 912<body>
309</section> 913
310</chapter> 914<p>
311<chapter> 915If your sound card lacks a hardware synthesizer, you could use a virtual one
312<title>Starting ALSA</title> 916like <c>timidity++</c>. Installation is a breeze.
917</p>
918
919<pre caption="Installing timidity++">
920# <i>emerge timidity++</i>
921</pre>
922
923<p>
924For timidity to play sounds, it needs a sound font. Fortunately, the ebuild will
925install some sound font packages for you. There are a few other font packages
926available in Portage, such as <c>timidity-freepats</c> and
927<c>timidity-eawpatches</c>. You can have multiple sound font configurations
928installed, and you can place your own in <path>/usr/share/timidity/</path>. To
929switch between different timidity configurations, you should use
930<c>eselect</c>.
931</p>
932
933<pre caption="Changing configurations">
934# <i>eselect timidity list</i>
935# <i>eselect timidity set eawpatches</i>
936</pre>
937
938<p>
939Don't forget to add <c>timidity</c> to the default runlevel.
940</p>
941
942<pre caption="Adding timidity to the default runlevel">
943# <i>rc-update add timidity default</i>
944# <i>/etc/init.d/timidity start</i>
945</pre>
946
947<p>
948You can now try out <uri link="#doc_chap4_pre3">Playing MIDI</uri> files.
949</p>
950
951</body>
313<section> 952</section>
314 <title>Adding alsasound to a runlevel</title>
315<body>
316<p>
317First thing to do now, is to make ALSA startup at boottime. Like this:
318<pre>
319# <i>rc-update add alsasound boot</i>
320</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> 953<section>
954<title>Tools and Firmware</title>
955<body>
956
957<p>
958Some specific sound cards can benefit from certain tools provided by the
959<c>alsa-tools</c> and <c>alsa-firmware</c> packages. You may install either with
960a simple <c>emerge</c>.
961</p>
962
963<pre caption="Installing ALSA Tools">
964# <i>emerge alsa-tools</i>
965</pre>
966
967</body>
327<section> 968</section>
328 <title>Running and unmuting</title>
329<body>
330<p>
331Since we're Linux users, we don't want to reboot. So we'll start the alsasound script manually.
332</p>
333<pre>
334# <i>/etc/init.d/alsasound start</i>
335</pre>
336<p>
337ALSA is running now. If everything is ok, you should be able to see the ALSA modules loaded when running <c>lsmod</c>.
338However, sound won't work yet, because the channels are still muted. We need <c>amixer</c> for this.
339</p>
340<pre caption = "Running amixer">
341# <i>amixer</i>
342</pre>
343<p>
344<warn>
345You 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<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# <i>modprobe snd-mixer-oss</i>
351# <i>modprobe snd-pcm-oss</i>
352# <i>amixer</i>
353</pre>
354<p>
355If you got this far, now unmute Master and PCM channels. Some hardware
356even requires you to unmute the center channel or even the surround
357channel.
358</p>
359<p>
360<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</pre>
369</p>
370We check to see if sound is working by using the aplay (alsa play) command. If you hear a pop, then sound is indeed working.
371Then, adjust the volume settings to your liking; the ncurses-based <c>alsamixer</c> is a great way to get them "just so".
372<p>
373You may want to emerge <c>alsa-xmms</c> as that will provide ALSA support for XMMS.
374</p>
375When you reboot your system, the <e>alsasound</e> init script will properly save and restore your volume settings.
376</body>
377</section> 969<section>
378</chapter> 970<title>Multiple sound cards</title>
379<chapter> 971<body>
380<title>Final Notes</title> 972
973<p>
974You can have more than one sound card in your system simultaneously, provided
975that you have built ALSA as modules in your kernel (or have installed
976<c>alsa-driver</c> instead). You just need to specify which should be started
977first in <path>/etc/modules.d/alsa</path>. Your cards are identified by their
978driver names inside this file. 0 is the first card, 1 is the second, and so on.
979Here's an example for a system with two sound cards.
980</p>
981
982<pre caption="Two sound cards in /etc/modules.d/alsa">
983options snd-emu10k1 index=0
984options snd-via82xx index=1
985</pre>
986
987<p>
988Or, if you have two cards that use the same driver, you specify them on the same
989line, using comma-separated numbers. Here's an example for a system with three
990sound cards, two of which are the same Intel High Definition Audio card.
991</p>
992
993<pre caption="Multiple sound cards in /etc/modules.d/alsa">
994options snd-ymfpci index=0
995options snd-hda-intel index=1,2
996</pre>
997
998</body>
381<section> 999</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
386have 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# <i>emerge alsa-driver</i>
390</pre>
391</body>
392</section> 1000<section>
1001<title>Plugins</title>
1002<body>
1003
1004<p>
1005You may want to install some plugins for extra functionality.
1006<c>alsa-plugins</c> is a collection of useful plugins, which include: PulseAudio
1007output, a sample rate converter, jack (a low-latency audio server), and an
1008encoder that lets you output 6-channel audio through digital S/PDIF connections
1009(both optical and coaxial). You can choose which of its plugins you want
1010installed by adding their USE flags to <path>/etc/portage/package.use</path>.
1011</p>
1012
1013<pre caption="Installing alsa-plugins">
1014# <i>emerge -avt alsa-plugins</i>
1015</pre>
1016
1017</body>
393<section> 1018</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
397load 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.
399Check the <uri link="http://www.djcj.org/LAU/guide/alsbook/faq1.html">this FAQ</uri> for more info.</p>
400</body>
401</section> 1019<section>
1020<title>A big thank you to...</title>
1021<body>
402 1022
1023<p>
1024Everyone who contributed to the earlier version of the Gentoo ALSA Guide:
1025Vincent Verleye, Grant Goodyear, Arcady Genkin, Jeremy Huddleston,
1026John P. Davis, Sven Vermeulen, Benny Chuang, Tiemo Kieft and Erwin.
1027</p>
1028
1029</body>
403<section> 1030</section>
404<title>Known bugs</title> 1031<section>
1032<title>References</title>
405<body> 1033<body>
406
407<note>
408This guide lags behind on the alsa-development. Chances are these bugs
409are already fixed when you read this.
410</note>
411 1034
412<ul> 1035<ul>
413<li> 1036 <li><uri link="http://www.alsa-project.org/">The ALSA Project</uri></li>
414If you have <b>lots of noise</b> when using <b>oss</b> emulation, add 1037 <li><uri link="http://linux-sound.org">Linux Sound/MIDI Software</uri></li>
415<e>options snd-pcm-oss dsp_map=1</e> to
416<path>/etc/modules.d/alsa</path>.
417</li>
418</ul> 1038</ul>
419 1039
420</body>
421</section>
422
423<section>
424 <title>More links..</title>
425<body>
426<p>
427You could check these for additional info:
428</p>
429<p>
430<ul>
431<li><uri link="http://www.gentoo.org/doc/en/desktop.xml">The Gentoo Linux Desktop Configuration Guide</uri></li>
432<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> 1040</body>
440</section> 1041</section>
441</chapter> 1042</chapter>
442</guide> 1043</guide>

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