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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 1.37 2004/06/15 07:21:07 bennyc Exp $ --> 2<!-- $Header: /var/cvsroot/gentoo/xml/htdocs/doc/en/alsa-guide.xml,v 1.74 2007/03/04 10:35:58 nightmorph Exp $ -->
3
3<!DOCTYPE guide SYSTEM "/dtd/guide.dtd"> 4<!DOCTYPE guide SYSTEM "/dtd/guide.dtd">
4 5
5<guide link = "/doc/en/alsa-guide.xml"> 6<guide link="/doc/en/alsa-guide.xml">
6<title>Gentoo Linux ALSA Guide</title> 7<title>Gentoo Linux ALSA Guide</title>
8
7<author title="Author"> 9<author title="Author">
8 <mail link="zu@pandora.be">Vincent Verleye</mail> 10 <mail link="fox2mike@gentoo.org">Shyam Mani</mail>
9</author> 11</author>
10<author title="Author"> 12<author title="Author">
11 <mail link="g2boojum@gentoo.org">Grant Goodyear</mail> 13 <mail link="nightmorph@gentoo.org">Joshua Saddler</mail>
12</author> 14</author>
13<author title="Author"> 15<author title="Contributor">
14 <mail link="agenkin@gentoo.org">Arcady Genkin</mail> 16 <mail link="flameeyes@gentoo.org">Diego Pettenò</mail>
15</author> 17</author>
16<author title="Author">
17 <mail link="eradicator@gentoo.org">Jeremy Huddleston</mail>
18</author>
19<author title="Editor"><!-- zhen@gentoo.org -->
20 John P. Davis
21</author>
22<author title="Editor">
23 <mail link="swift@gentoo.org">Sven Vermeulen</mail>
24</author>
25<author title="Editor">
26 <mail link="bennyc@gentoo.org">Benny Chuang</mail>
27</author>
28<author title="Editor">
29 <mail link="blubber@gentoo.org">Tiemo Kieft</mail>
30</author>
31<author title="Editor">
32 <mail link="erwin@gentoo.org">Erwin</mail>
33</author>
34 18
35<abstract> 19<abstract>
36This guide will show you how to set up the Advanced Linux Sound Architecture 20This document helps a user setup ALSA on Gentoo Linux.
37(ALSA) on Gentoo Linux. In addition to the Gentoo Linux Desktop Configuration
38Guide, this guide is supposed to give you more information on this subject.
39</abstract> 21</abstract>
40 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 -->
41<license/> 25<license/>
42 26
43<version>1.5.0</version> 27<version>2.17</version>
44<date>May 18, 2004</date> 28<date>2007-02-17</date>
45 29
46<chapter> 30<chapter>
47<title>The Advanced Linux Sound Architecture</title> 31<title>Introduction</title>
48<section> 32<section>
49<title>What is ALSA?</title> 33<title>What is ALSA?</title>
50<body> 34<body>
51 35
52<p> 36<p>
53ALSA is the <e>Advanced Linux Sound Architecture</e>, a project dedicated to the 37ALSA, which stands for <e>Advanced Linux Sound Architecture</e>, provides
54development of a high-quality Linux sound subsystem. It has replaced OSS 38audio and MIDI (<e>Musical Instrument Digital Interface</e>) functionality to
55(<e>Open Sound System</e>) as default sound subsystem in the 2.6 kernel series. 39the Linux operating system. ALSA is the default sound subsystem in the 2.6
56</p> 40kernel thereby replacing OSS (<e>Open Sound System</e>), which was used in the
57 412.4 kernels.
58<p> 42</p>
59ALSA provides efficient support for all types of audio interfaces, is fully 43
60modularized, is SMP and thread-safe and provides a high-quality user space 44<p>
61library called <e>alsa-lib</e> to simplify application programming. It also 45ALSA's main features include efficient support for all types of audio
62provides a backwards compatibility layer with OSS. 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
52</body>
53</section>
54<section>
55<title>ALSA on Gentoo</title>
56<body>
57
58<p>
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.
63</p> 63</p>
64 64
65</body> 65</body>
66</section> 66</section>
67</chapter> 67</chapter>
68
68<chapter> 69<chapter>
69<title>Installing ALSA</title> 70<title>Installing ALSA</title>
70<section> 71<section>
71<title>USE Flags</title> 72<title>Options</title>
72<body>
73
74<p>
75Gentoo provides an <c>alsa</c> USE flag which you should set in
76<path>/etc/make.conf</path> to allow our available packages to compile with
77ALSA support. If you have <c>oss</c> in your USE variable as well, ALSA will
78compile with OSS backward compatibility.
79</p>
80
81</body> 73<body>
82</section> 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
80<p>
81The two options are :
82</p>
83
84<ol>
85 <li>Use ALSA provided by your kernel.</li>
86 <li>Use Gentoo's <c>media-sound/alsa-driver</c> package.</li>
87</ol>
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>
83<section> 153</section>
84<title>Kernel Modules</title> 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
85<body> 169</body>
170</section>
171<section id="lspci">
172<title>Before you proceed</title>
173<body>
86 174
87<p>
88First of all, before continuing, make sure your kernel has <e>Sound Card
89Support</e> enabled. If you used <c>genkernel</c> to build your kernel, then
90this is automatically true. Otherwise reconfigure your kernel.
91</p> 175<p>
92 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.
93<p> 184</p>
94If you use a 2.6 kernel you can skip the rest of this section and continue with 185
95<uri link="#alsa-utils">Installing the ALSA Utils</uri> as 2.6 already has the 186<ul>
96necessary ALSA drivers in it. Of course, don't forget to enable support for the 187 <li>
97sound card you have when configuring your kernel. 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>
199</ul>
200
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
98</p> 206<p>
99 207We now proceed to find out details about the sound card.
100<p> 208</p>
101Users of 2.4 kernel sources will have to install the necessary ALSA drivers for 209
102their soundcard. First find out what soundcard you have. An easy trick is to 210<pre caption="Soundcard Details">
103search for "audio" in <path>/proc/pci</path>: 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
104</p> 215<p>
105 216We now know that the sound card on the machine is a Sound Blaster Live! and
106<pre caption="Finding out the soundcard type"> 217the card manufacturer is Creative Labs. Head over to the
107# <i>grep -i audio /proc/pci</i> 218<uri link="http://www.alsa-project.org/alsa-doc/"> ALSA Soundcard Matrix</uri>
108Multimedia audio controller: VIA Technologies, Inc. VT82C686 AC97 Audio 219page and select Creative Labs from the drop down menu. You will be taken to
109Controller (rev 64). 220the Creative Labs matrix page where you can see that the SB Live! uses the
110</pre> 221<c>emu10k1</c> module. That is the information we need for now. If you are
111 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.
112<p> 224</p>
113Now go to the <uri link="http://www.alsa-project.org/alsa-doc">ALSA Soundcard 225
114Matrix</uri> and search for your soundcard. In the above example you should go
115to the "VIA" manufacturer. You will receive a table with the known chipsets of
116that vendor. The chipset in the above example is "via82c686"; the "Details" link
117then informs me that the driver is called <path>via82xx</path>.
118</p> 226<p>
119 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>.
120<p> 230</p>
121Based on this information we can now install the <c>alsa-driver</c> for our 231
122soundcard. First edit <path>/etc/make.conf</path> and <e>add</e> a new option 232<pre caption="MIDI support in /etc/make.conf">
123called ALSA_CARDS to it. Inside this variable you declare the soundcard driver 233<comment>(If you want MIDI support)</comment>
124you want to use: 234USE="midi"
235
236<comment>(If you don't need MIDI)</comment>
237USE="-midi"
238</pre>
239
240</body>
241</section>
242<section id="kernel">
243<title>Using ALSA provided by your Kernel</title>
244<body>
245
125</p> 246<p>
126 247If you're a person who likes to keep things simple like I do, then this is
127<pre caption="Editing /etc/make.conf for ALSA_CARDS"> 248the way to go.
128ALSA_CARDS="via82xx"
129</pre>
130
131<p> 249</p>
132Now install <c>alsa-driver</c>: 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
133</p> 258<p>
259Let us now configure the kernel to enable ALSA.
260</p>
134 261
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>
348</section>
349<section id="alsa-driver">
350<title>Using the ALSA Driver package</title>
351<body>
352
353<p>
354So you've decided to go the <c>alsa-driver</c> way. Let's get started then.
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
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
135<pre caption="Installing ALSA Drivers"> 418<pre caption="Installing alsa-driver">
136# <i>emerge alsa-driver</i> 419# <i>emerge alsa-driver</i>
137</pre> 420</pre>
138 421
139<impo> 422<impo>
140Whenever you (re)compile your kernel sources, chances are that the ALSA drivers 423Please note that you will have to run <c>emerge alsa-driver</c> after every
141will be overwritten. It is therefore adviseable to rerun <c>emerge 424kernel (re)compile, as the earlier drivers are deleted. To make this task
142alsa-driver</c> every time you (re)compile your kernel <e>after</e> having 425easier, you may want to emerge the <c>module-rebuild</c> package, which will
143rebooted into the new kernel. 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.
144</impo> 430</impo>
145 431
146</body> 432</body>
147</section> 433</section>
434</chapter>
435
436<chapter>
437<title>Configuring/Testing ALSA</title>
148<section id="alsa-utils"> 438<section id="alsa-utilities">
149<title>Installing the ALSA Utils</title> 439<title>ALSA Utilities</title>
150<body> 440<body>
151 441
152<p>
153If you want backwards compatibility with OSS, you need to install
154<c>alsa-oss</c>:
155</p> 442<p>
156 443<c>alsa-utils</c> forms an integral part of ALSA as it has a truckload of
157<pre caption="Installing the ALSA OSS compatibility layer"> 444programs that are highly useful, including the ALSA Initscripts. Hence we
158# <i>emerge alsa-oss</i> 445strongly recommend that you install <c>alsa-utils</c>
159</pre>
160
161<p> 446</p>
162Now install the ALSA Utils on your system (this is mandatory):
163</p>
164 447
165<pre caption="Installing ALSA Utils"> 448<pre caption="Install alsa-utils">
166# <i>emerge alsa-utils</i> 449# <i>emerge alsa-utils</i>
167</pre> 450</pre>
168 451
452<note>
453If you activated ALSA in your <uri link="#kernel">kernel</uri> <e>and</e> did
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>.
458</note>
459
460</body>
461</section>
462<section id="alsa-config">
463<title>Configuration</title>
464<body>
465
466<p>
467Recent versions of <c>udev</c> (<c>>=udev-103</c>) provide some degree of
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.
169<p> 471</p>
170Now that the utils are installed, it is time to configure ALSA... 472
473<note>
474Please shut down any programs that <e>might</e> access the sound card while
475running <c>alsaconf</c>.
476</note>
477
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>
485</pre>
486
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.
515</pre>
516
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.
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
573<impo>
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.
579</impo>
580
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.
586</p>
587
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.
618</note>
619
620<p>
621After you're all done, your ALSA Mixer should look similar to the one below.
622Note the 00 instead of the MM and also the volume levels for some optimum
623settings.
624</p>
625
626<figure link="/images/docs/alsa-mixerunmuted.png" short="AlsaMixer Unmuted" caption="Alsa Mixer ready to roll"/>
627
628</body>
629</section>
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
679</body>
680</section>
681<section>
682<title>ALSA and USE</title>
683<body>
684
685<p>
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.
689</p>
690
691</body>
692</section>
693<section>
694<title>Issues?</title>
695<body>
696
697<p>
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.
702</p>
703
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.
708</p>
709
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
747</pre>
748
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.
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.
171</p> 837</p>
172 838
173</body> 839</body>
174</section> 840</section>
175</chapter> 841</chapter>
842
176<chapter> 843<chapter>
177<title>Configuring ALSA</title> 844<title>Other things ALSA</title>
178<section> 845<section id="midi">
179<title>Automatically Loading the Kernel Modules</title> 846<title>Setting up MIDI support</title>
180<body>
181
182<p>
183If you use a modular kernel (such as when using <c>genkernel</c>) you have to
184edit <path>/etc/modules.d/alsa</path> so that it activates the necesary modules
185at boot time. For the soundcard in our example:
186</p>
187
188<pre caption="/etc/modules.d/alsa">
189alias snd-card-0 snd-via82xx
190<comment># The following is only needed when you want OSS compatibility</comment>
191alias sound-slot-0 snd-card-0
192alias /dev/mixer snd-mixer-oss
193alias /dev/dsp snd-pcm-oss
194alias /dev/midi snd-seq-oss
195</pre>
196
197<p>
198Now run <c>modules-update</c> to save the changes you made to the
199<path>alsa</path> file into <path>/etc/modules.conf</path>:
200</p>
201
202<pre caption="Running modules-update">
203# <i>modules-update</i>
204</pre>
205
206</body> 847<body>
207</section>
208<section>
209<title>Verifying the Device Files</title>
210<body>
211 848
212<p>
213If you use DevFS (which is the default for Gentoo installations) make sure that
214<path>/etc/devfsd.conf</path> has the ALSA devices and permissions correctly
215registered:
216</p> 849<p>
217 850First, check to make sure that you enabled the <c>midi</c> USE flag in
218<pre caption="/etc/devfsd.conf"> 851<path>/etc/make.conf</path>.
219# ALSA/OSS stuff
220# Comment/change these if you want to change the permissions on
221# the audio devices
222LOOKUP snd MODLOAD ACTION snd
223LOOKUP dsp MODLOAD
224LOOKUP mixer MODLOAD
225LOOKUP midi MODLOAD
226REGISTER sound/.* PERMISSIONS root.audio 660
227REGISTER snd/.* PERMISSIONS root.audio 660
228</pre>
229
230</body>
231</section>
232<section>
233<title>Having ALSA Activated at Boot</title>
234<body>
235
236<p> 852</p>
237To activate ALSA support at boot, add the <c>alsasound</c> init script to the 853
238boot runlevel: 854<pre caption="MIDI support in /etc/make.conf">
855USE="midi"
856</pre>
857
239</p> 858<p>
240 859If you didn't previously enable <c>midi</c>, go ahead and add it to
241<pre caption="Adding alsasound to the boot runlevel"> 860<path>/etc/make.conf</path> now. You will also need to re-emerge any ALSA
242# <i>rc-update add alsasound boot</i> 861packages that use the <c>midi</c> flag, such as <c>alsa-lib</c>,
243# <i>/etc/init.d/alsasound start</i> 862<c>alsa-utils</c>, and <c>alsa-driver</c>.
244</pre>
245
246</body>
247</section>
248<section>
249<title>Unmute the Channels</title>
250<body>
251
252<p> 863</p>
253By default, all sound channels are muted. To fix this, run <c>amixer</c>: 864
254</p> 865<p>
255 866If your sound card is one of those that come with on-board MIDI synthesizers
256<pre caption="Running amixer"> 867and you would like to listen to some .mid files, you have to install
257# <i>amixer</i> 868<c>awesfx</c> which is basically a set of utilities for controlling the AWE32
258</pre> 869driver. We need to install it first. If you don't have a hardware synthesizer,
259 870you can use a virtual one. Please see the section on
871<uri link="#vsynth">Virtual Synthesizers</uri> for more information.
260<p> 872</p>
261If <c>amixer</c> produces lots of output then you're ready to unmute the
262channels. If you receive an error, doublecheck that your soundcard module is
263started.
264</p>
265 873
266<p>
267Now unmute the <e>Master</e> and <e>PCM</e> channels. If this isn't sufficient,
268also unmute the <e>Center</e> and <e>Surround</e> channels.
269</p>
270
271<pre caption="Unmuting the sound channels">
272# <i>amixer set Master 100 unmute</i>
273# <i>amixer set PCM 100 unmute</i>
274<comment>(Only if the above isn't sufficient:)</comment>
275# <i>amixer set Center 100 unmute</i>
276# <i>amixer set Surround 100 unmute</i>
277</pre>
278
279<p>
280To check if your sound works, play a wave file (using <c>aplay</c>), mp3 (using
281<c>mpg123</c> or even <c>mplayer</c>) or any other sound file for that matter.
282</p>
283
284<p>
285To fine-tune the sound channel settings you can use the <c>alsamixer</c>
286application.
287</p>
288
289</body>
290</section>
291</chapter>
292<chapter>
293<title>Activating MIDI Support</title>
294<section>
295<title>Installing the Necessary Packages</title>
296<body>
297
298<p>
299Some soundcards come with onboard MIDI synthesizers. To use them, you must first
300install the <c>awesfx</c> package:
301</p>
302
303<pre caption="Installing the awesfx package"> 874<pre caption="Installing awesfx">
304# <i>emerge awesfx</i> 875# <i>emerge awesfx</i>
305</pre> 876</pre>
306 877
307<p> 878<note>
308If you have a collection of sound fonts somewhere, place them in 879You will need to copy over SoundFont (SF2) files from your sound card's driver
309<path>/usr/share/sfbank</path>. For instance, the SBLive has a sound font file 880CD or a Windows installation into <path>/usr/share/sounds/sf2/</path>. For
310called <path>8MBGMSFX.SF2</path> or <path>CT4GMSFX.SF2</path>. 881example a sound font file for the Creative SBLive! card would be 8MBGMSFX.SF2.
882</note>
883
311</p> 884<p>
312 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.
313<p> 889</p>
314After copying over the sound font, select them using <c>sfxload</c>:
315</p>
316 890
891<note>
892<path>/mnt</path> paths mentioned in the code listing(s) below will <e>not</e>
893be the same in your machine. They are just an example. Please be careful to
894change the path to suit your machine.
895</note>
896
317<pre caption="Loading the sound font"> 897<pre caption="Loading Soundfonts">
898<comment>(First, copy the Soundfont)</comment>
899# <i>cp /mnt/win2k/Program\ Files/CreativeSBLive2k/SFBank/8MBGMSFX.SF2 /usr/share/sounds/sf2/</i>
900<comment>(Or get it from your SoundBlaster CD)</comment>
901# <i>cp /mnt/cdrom/AUDIO/ENGLISH/SFBANK/8MBGMSFX.SF2 /usr/share/sounds/sf2/</i>
902<comment>(We load the specific Soundfont)</comment>
318# <i>sfxload /usr/share/sfbank/8MBGMSFX.SF2</i> 903# <i>asfxload /usr/share/sounds/sf2/8MBGMSFX.SF2</i>
319</pre> 904</pre>
320 905
321<p>
322You must have this command run every time you boot, so it is adviseable to add
323it to <path>/etc/conf.d/local.start</path> as well.
324</p> 906<p>
325 907You can now play midi files using a program like <c>aplaymidi</c>. Run
908<c>aplaymidi -l</c> to get a list of available ports and then pick one
909to play the file on.
326<p> 910</p>
327If you can't find soundfonts on your driver CD you can download some online from 911
328<uri>http://www.parabola.demon.co.uk/alsa/awe64.html</uri>. 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>
329</p> 923</pre>
330 924
331</body> 925</body>
332</section>
333<section> 926</section>
927<section id="vsynth">
334<title>Timidity++ Virtual Synthesizer</title> 928<title>Virtual Synthesizers</title>
335<body> 929<body>
336 930
337<p>
338If your sound card does not come with a hardware synthesizer (or you don't want
339to use it), you can use <c>timidity++</c> to provide you with a virtual
340synthesizer. Start by emerging this package:
341</p> 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>
342 935
343<pre caption="Installing Timidity++"> 936<pre caption="Installing timidity++">
344# <i>emerge timidity++</i> 937# <i>emerge timidity++</i>
345</pre> 938</pre>
346 939
347<p> 940<p>
348A sample configuration file will be installed for you in 941For timidity to play sounds, it needs a sound font. Fortunately, the ebuild will
349<path>/usr/share/timidity/config/timidity.cfg</path>. If you don't have a 942install some sound font packages for you. There are a few other font packages
350timidity++ configuration setup yet, you can just use this one. 943available in Portage, such as <c>timidity-freepats</c> and
351</p> 944<c>timidity-eawpatches</c>. You can have multiple sound font configurations
352 945installed, and you can place your own in <path>/usr/share/timidity/</path>. To
353<pre caption="Using the default Timidity++ configuration file"> 946switch between different timidity configurations, you should use
354# <i>cp /usr/share/timidity/config/timidity.cfg /usr/share/timidity</i> 947<c>eselect</c>.
355</pre>
356
357<p> 948</p>
358For timidity to play sounds, it needs a soundfont. If you do not have any,
359install <c>timidity-eawpatches</c> which will give you some soundfonts.
360</p>
361 949
362<pre caption="Installing timidity-eawpatches"> 950<pre caption="Changing configurations">
951# <i>eselect timidity list</i>
363# <i>emerge timidity-eawpatches</i> 952# <i>eselect timidity set eawpatches</i>
364</pre> 953</pre>
365 954
366<p> 955<p>
367Don't forget to add <c>timidity</c> to the default runlevel. 956Don't forget to add <c>timidity</c> to the default runlevel.
368</p> 957</p>
370<pre caption="Adding timidity to the default runlevel"> 959<pre caption="Adding timidity to the default runlevel">
371# <i>rc-update add timidity default</i> 960# <i>rc-update add timidity default</i>
372# <i>/etc/init.d/timidity start</i> 961# <i>/etc/init.d/timidity start</i>
373</pre> 962</pre>
374 963
964<p>
965You can now try out <uri link="#doc_chap4_pre3">Playing MIDI</uri> files.
966</p>
967
375</body> 968</body>
376</section>
377<section> 969</section>
378<title>Testing MIDI Support</title>
379<body>
380
381<p>
382You can use <c>pmidi</c> to test your MIDI configuration:
383</p>
384
385<pre caption="Installing pmidi">
386# <i>emerge pmidi</i>
387</pre>
388
389<p>
390To see what MIDI output ports are available on your system, use the <c>-l</c>
391option:
392</p>
393
394<pre caption="Viewing the MIDI output ports">
395# <i>pmidi -l</i>
396</pre>
397
398<p>
399If all looks fine, try playing a MIDI file to make sure everything works. With
400the <c>-p</c> option you define what MIDI port you want to use.
401</p>
402
403<pre caption="Playing a MIDI file">
404# <i>pmidi -p 65:0 "Final Fantasy 7 - Aerith' Theme.mid"</i>
405</pre>
406
407</body>
408</section>
409</chapter>
410<chapter>
411<title>Final Remarks</title>
412<section> 970<section>
413<title>Tools and Firmware</title> 971<title>Tools and Firmware</title>
414<body> 972<body>
415 973
416<p> 974<p>
417Some specific sound cards can benefit from certain tools provided by the 975Some specific sound cards can benefit from certain tools provided by the
418<c>alsa-tools</c> and <c>alsa-firmware</c> packages. If you need 976<c>alsa-tools</c> and <c>alsa-firmware</c> packages. You may install either with
419<c>alsa-tools</c>, be sure to define the ALSA_TOOLS variable in 977a simple <c>emerge</c>.
420<path>/etc/make.conf</path> with the tools you require. For instance:
421</p>
422
423<pre caption="Selecting ALSA Tools in /etc/make.conf">
424ALSA_TOOLS="as10k1 ac3dec"
425</pre>
426
427<p>
428Then install the <c>alsa-tools</c> (and/or <c>alsa-firmware</c>) package(s):
429</p> 978</p>
430 979
431<pre caption="Installing ALSA Tools"> 980<pre caption="Installing ALSA Tools">
432# <i>emerge alsa-tools</i> 981# <i>emerge alsa-tools</i>
433</pre> 982</pre>
434 983
435</body> 984</body>
436</section> 985</section>
437<section> 986<section>
438<title>Activating Joystick Support</title> 987<title>Multiple sound cards</title>
439<body>
440
441<p>
442If your soundcard has a joystick plug, you might be interested in activating
443joystick support for your soundcard. If so, start by verifying if your soundcard
444driver has a joystick parameter. You can verify this by running <c>modinfo</c>
445against your kernel module. For instance, for the <c>snd-via82xx</c>:
446</p>
447
448<pre caption="Running modinfo">
449# <i>modinfo snd-via82xx</i>
450filename: /lib/modules/2.4.22-ck2/snd-via82xx.o
451description: "VIA VT82xx audio"
452author: "Jaroslav Kysela &lt;perex@suse.cz&gt;"
453license: "GPL"
454parm: index int array (min = 1, max = 8), description "Index value for
455 VIA 82xx bridge."
456parm: id string array (min = 1, max = 8), description "ID string for VIA
457 82xx bridge."
458parm: enable int array (min = 1, max = 8), description "Enable audio part
459 of VIA 82xx bridge."
460parm: mpu_port long array (min = 1, max = 8), description "MPU-401 port.
461 (VT82C686x only)"
462<i>parm: joystick int array (min = 1, max = 8), description "Enable
463 joystick. (VT82C686x only)"</i>
464parm: ac97_clock int array (min = 1, max = 8), description "AC'97 codec
465 clock (default 48000Hz)."
466parm: dxs_support int array (min = 1, max = 8), description "Support for
467 DXS channels (0 = auto, 1 = enable, 2 = disable, 3 = 48k only, 4 =
468 no VRA)
469</pre>
470
471<p>
472If it has the <c>joystick</c> parameter, append <c>joystick=1</c> to your
473<c>options</c> line in <path>/etc/modules.d/alsa</path>. For instance:
474</p>
475
476<pre caption="Adding the joystick parameter">
477alias snd-card-0 snd-via82xx
478options snd-via82xx joystick=1
479</pre>
480
481</body> 988<body>
482</section> 989
990<p>
991You can have more than one sound card in your system simultaneously, provided
992that you 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>
483<section> 1016</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>
1035</section>
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
1046</body>
1047</section>
1048<section>
484<title>Resources</title> 1049<title>References</title>
485<body> 1050<body>
486 1051
487<ul> 1052<ul>
488 <li><uri link="http://www.alsa-project.org">The ALSA Project</uri></li> 1053 <li><uri link="http://www.alsa-project.org/">The ALSA Project</uri></li>
489 <li><uri link="http://www.djcj.org">ALSA Howto's and FAQs</uri></li>
490 <li><uri link="http://linux-sound.org">Linux Sound/MIDI Software</uri></li> 1054 <li><uri link="http://linux-sound.org">Linux Sound/MIDI Software</uri></li>
491</ul> 1055</ul>
492 1056
493</body> 1057</body>
494</section> 1058</section>

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