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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 1.79 2007/05/07 07:08:24 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>2.22</version>
44<date>May 18, 2004</date> 28<date>2007-05-07</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>
86 Use ALSA provided by your kernel. This is the preferred/recommended method.
87 </li>
88 <li>Use Gentoo's <c>media-sound/alsa-driver</c> package.</li>
89</ol>
90
91<p>
92The in-kernel drivers and the <c>alsa-driver</c> package can vary a little; it's
93possible that features and fixes found in one might not yet be incorporated into
94the other. The upstream developers are aware of this, but the two drivers are
95effectively separate branches of the ALSA project; they are not entirely
96identical. You should be aware that they might function slightly differently, so
97if one doesn't work for you, try the other! We shall take a peek into both
98before finally deciding on one.
99</p>
100
101<p>
102If you were to use ALSA provided by the kernel, the following are the pros and
103cons:
104</p>
105
106<table>
107<tr>
108 <th>Kernel ALSA</th>
109 <th>Pros and Cons</th>
110</tr>
111<tr>
112 <th>+</th>
113 <ti>
114 No need to emerge yet another package; drivers are integrated into kernel.
115 </ti>
116</tr>
117<tr>
118 <th>+</th>
119 <ti>One shot solution, no repeating emerges.</ti>
120</tr>
121<tr>
122 <th>-</th>
123 <ti>Might be a slightly different version than <c>alsa-driver</c>.</ti>
124</tr>
125</table>
126
127<p>
128And, if you were to use <c>alsa-driver</c>,
129</p>
130
131<table>
132<tr>
133 <th>alsa-driver</th>
134 <th>Pros and Cons</th>
135</tr>
136<tr>
137 <th>+</th>
138 <ti>Possibly the latest drivers from the ALSA Project.</ti>
139</tr>
140<tr>
141 <th>+</th>
142 <ti>Useful if you intend to develop audio drivers.</ti>
143</tr>
144<tr>
145 <th>-</th>
146 <ti>Every kernel recompile requires a re-emerge of <c>alsa-driver</c>.</ti>
147</tr>
148<tr>
149 <th>-</th>
150 <ti>Needs certain kernel config options disabled to work correctly.</ti>
151</tr>
152</table>
153
154</body>
83<section> 155</section>
84<title>Kernel Modules</title> 156<section>
157<title>So...</title>
158<body>
159
160<p>
161The differences between <c>alsa-driver</c> and the in-kernel ALSA drivers are
162quite subtle, as mentioned earlier. Since there are not any huge differences,
163you are encouraged to go through the process of using the ALSA provided by the
164kernel <e>first</e> for ease of use. Before reporting any sound related issues
165to <uri link="https://bugs.gentoo.org">Gentoo Bugzilla</uri>, please try to
166reproduce them using <c>alsa-driver</c> and file the bug report no matter what
167the result.
168</p>
169
85<body> 170</body>
171</section>
172<section id="lspci">
173<title>Before you proceed</title>
174<body>
86 175
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> 176<p>
92 177Whichever method of install you choose, you need to know what drivers your
178sound card uses. In most cases, sound cards (onboard and otherwise) are PCI
179based and <c>lspci</c> will help you in digging out the required information.
180Please <c>emerge sys-apps/pciutils</c> to get <c>lspci</c>, if you don't have it
181installed already. In case you have a USB sound card, <c>lsusb</c> from
182<c>sys-apps/usbutils</c> <e>might</e> be of help. For ISA cards, try using
183<c>sys-apps/isapnptools</c>. Also, the following pages <e>may</e> help users
184with ISA based sound cards.
93<p> 185</p>
94If you use a 2.6 kernel you can skip the rest of this section and continue with 186
95<uri link="#alsa-utils">Installing the ALSA Utils</uri> as 2.6 already has the 187<ul>
96necessary ALSA drivers in it. Of course, don't forget to enable support for the 188 <li>
97sound card you have when configuring your kernel. 189 <uri link="http://www.roestock.demon.co.uk/isapnptools/">The ISAPNPTOOLS
190 Page</uri>
191 </li>
192 <li>
193 <uri link="http://www2.linuxjournal.com/article/3269">LinuxJournal PnP
194 Article</uri>
195 </li>
196 <li>
197 <uri link="http://www.tldp.org/HOWTO/Sound-HOWTO/x320.html">TLDP Sound
198 HowTo</uri>
199 </li>
200</ul>
201
202<note>
203For ease of use/explanation, we assume the user has a PCI based sound card for
204the remainder of this guide.
205</note>
206
98</p> 207<p>
99 208We now proceed to find out details about the sound card.
100<p> 209</p>
101Users of 2.4 kernel sources will have to install the necessary ALSA drivers for 210
102their soundcard. First find out what soundcard you have. An easy trick is to 211<pre caption="Soundcard Details">
103search for "audio" in <path>/proc/pci</path>: 212# <i>lspci -v | grep -i audio</i>
2130000:00:0a.0 Multimedia audio controller: Creative Labs SB Live! EMU10k1 (rev 06)
214</pre>
215
104</p> 216<p>
105 217We now know that the sound card on the machine is a Sound Blaster Live! and the
106<pre caption="Finding out the soundcard type"> 218card manufacturer is Creative Labs. Head over to the <uri
107# <i>grep -i audio /proc/pci</i> 219link="http://bugtrack.alsa-project.org/main/index.php/Matrix:Main">ALSA
108Multimedia audio controller: VIA Technologies, Inc. VT82C686 AC97 Audio 220Soundcard Matrix</uri> page and select Creative Labs from the drop down menu.
109Controller (rev 64). 221You will be taken to the Creative Labs matrix page where you can see that the SB
110</pre> 222Live! uses the <c>emu10k1</c> module. That is the information we need for now.
111 223If you are interested in detailed information, you can click on the link next to
224the "Details" and that will take you to the <c>emu10k1</c> specific page.
112<p> 225</p>
113Now go to the <uri link="http://www.alsa-project.org/alsa-doc">ALSA Soundcard 226
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> 227<p>
119 228If you intend to use MIDI, then you should add <c>midi</c> to your USE flags in
229<path>/etc/make.conf</path> before emerging any ALSA packages. Later in the
230guide, we will show you how to set up <uri link="#midi">MIDI support</uri>.
120<p> 231</p>
121Based on this information we can now install the <c>alsa-driver</c> for our 232
122soundcard. First edit <path>/etc/make.conf</path> and <e>add</e> a new option 233</body>
123called ALSA_CARDS to it. Inside this variable you declare the soundcard driver 234</section>
124you want to use: 235<section id="kernel">
236<title>Using ALSA provided by your Kernel</title>
237<body>
238
125</p> 239<p>
126 240If you're a person who likes to keep things simple, then this is the way to go.
127<pre caption="Editing /etc/make.conf for ALSA_CARDS">
128ALSA_CARDS="via82xx"
129</pre>
130
131<p> 241</p>
132Now install <c>alsa-driver</c>: 242
243<note>
244Since the 2005.0 release, Gentoo Linux uses 2.6 as the default kernel. Please
245check that your kernel is a 2.6 series kernel. This method will <e>not</e> work
246on a 2.4 kernel.
247</note>
248
133</p> 249<p>
250Let us now configure the kernel to enable ALSA.
251</p>
134 252
253<impo>
254<c>genkernel</c> users should now run <c>genkernel --menuconfig all</c> and
255then follow the instructions in <uri link="#doc_chap2_pre3">Kernel Options for
256ALSA</uri>.
257</impo>
258
259<pre caption="Heading over to the source">
260# <i>cd /usr/src/linux</i>
261# <i>make menuconfig</i>
262</pre>
263
264<note>
265The above example assumes that <path>/usr/src/linux</path> symlink points to
266the kernel sources you want to use. Please ensure the same before proceeding.
267</note>
268
269<p>
270Now we will look at some of the options we will have to enable in the 2.6
271kernel to ensure proper ALSA support for our sound card.
272</p>
273
274<p>
275Please note that for ease of use, all examples show ALSA built as modules. It
276is advisable to follow the same as it then allows the use of <c>alsaconf</c>
277which is a boon when you want to configure your card. Please do <e>not</e> skip
278the <uri link="#alsa-config">Configuration</uri> section of this document. If
279you still like to have options built-in, ensure that you make changes to your
280config accordingly.
281</p>
282
283<pre caption="Kernel Options for ALSA">
284Device Drivers ---&gt;
285 Sound ---&gt;
286
287<comment>(This needs to be enabled)</comment>
288&lt;M&gt; Sound card support
289
290<comment>(Make sure OSS is disabled)</comment>
291Open Sound System ---&gt;
292 &lt; &gt; Open Sound System (DEPRECATED)
293
294<comment>(Move one step back and enter ALSA)</comment>
295Advanced Linux Sound Architecture ---&gt;
296 &lt;M&gt; Advanced Linux Sound Architecture
297 <comment>(Select this if you want MIDI sequencing and routing)</comment>
298 &lt;M&gt; Sequencer support
299 <comment>(Old style /dev/mixer* and /dev/dsp* support. Recommended.)</comment>
300 &lt;M&gt; OSS Mixer API
301 &lt;M&gt; OSS PCM (digital audio) API
302
303<comment>(You now have a choice of devices to enable support for. Generally,
304you will have one type of device and not more. If you have more than one
305sound card, please enable them all here.)</comment>
306
307<comment>(Mostly for testing and development purposes, not needed for normal
308users unless you know what you are doing.)</comment>
309Generic devices ---&gt;
310
311<comment>(For ISA Sound cards)</comment>
312ISA devices ---&gt;
313<comment>(IF you had the Gravis, you would select this option)</comment>
314 &lt;M&gt; Gravis UltraSound Extreme
315
316<comment>(Move one level back and into PCI devices. Most sound cards today are
317PCI devices)</comment>
318PCI devices ---&gt;
319 <comment>(We now select the emu10k1 driver for our card)</comment>
320 &lt;M&gt; Emu10k1 (SB Live!, Audigy, E-mu APS)
321 <comment>(Or an Intel card would be)</comment>
322 &lt;M&gt; Intel/SiS/nVidia/AMD/ALi AC97 Controller
323 <comment>(Or if you have a VIA Card)</comment>
324 &lt;M&gt; VIA 82C686A/B, 8233/8235 AC97 Controller
325
326<comment>(Move one level back and select in case you have an USB sound card)</comment>
327USB Devices ---&gt;
328</pre>
329
330<p>
331Now that your options are set, you can (re)compile the kernel and ALSA support
332for your card should be functional once you reboot into the new kernel. Don't
333forget to update your GRUB configuration to use the newly built kernel.
334You can now proceed to <uri link="#alsa-utilities">ALSA Utilities</uri> and
335see if everything is working as it should.
336</p>
337
338</body>
339</section>
340<section id="alsa-driver">
341<title>Using the ALSA Driver package</title>
342<body>
343
344<p>
345So you've decided to go the <c>alsa-driver</c> way. Let's get started then.
346There are a few minor things to be done to ensure only the drivers for your
347sound card are compiled. Although this is not really necessary, it cuts down
348on the unnecessary drivers that will be compiled otherwise.
349</p>
350
351<p>
352If you don't have an idea of what drivers your sound card might need, please
353take a look at the <uri link="#lspci">lspci</uri> section of this guide. Once
354you have your driver name (<c>emu10k1</c> in our example), edit
355<path>/etc/make.conf</path> and add a variable, <c>ALSA_CARDS</c>.
356</p>
357
358<pre caption="Adding ALSA_CARDS to make.conf">
359<comment>(For one sound card)</comment>
360ALSA_CARDS="emu10k1"
361<comment>(For more than one, separate names with spaces)</comment>
362ALSA_CARDS="emu10k1 via82xx"
363</pre>
364
365<p>
366If you have compiled your kernel and want to use <c>alsa-driver</c>, please
367ensure the following before proceeding, else <c>alsa-driver</c> is likely to
368fail. The next code listing gives you one way of performing the checks.
369</p>
370
371<note>
372<c>genkernel</c> users can proceed with <uri link="#doc_chap2_pre6">Installing
373alsa-driver</uri> as their configuration is in sync with the one shown below by
374default.
375</note>
376
377<ol>
378 <li>
379 <c>CONFIG_SOUND</c> is set. (Basic Sound support enabled)
380 </li>
381 <li>
382 <c>CONFIG_SOUND_PRIME</c> is not set. (In-built OSS support disabled)
383 </li>
384 <li>
385 <c>CONFIG_SND</c> is not set. (In-built ALSA support disabled)
386 </li>
387 <li>
388 <path>/usr/src/linux</path> points to the kernel you want ALSA working on.
389 </li>
390</ol>
391
392<pre caption=".config checks">
393<comment>(Assuming the linux symlink points to the correct kernel)</comment>
394# <i>cd /usr/src/linux</i>
395# <i>grep SOUND .config</i>
396<comment>(1. is true)</comment>
397CONFIG_SOUND=y
398<comment>(2. is true)</comment>
399CONFIG_SOUND_PRIME is not set
400# <i>grep SND .config</i>
401<comment>(and 3. is true)</comment>
402CONFIG_SND is not set
403</pre>
404
405<p>
406Now all you have to do is type the magic words... and no, it's not abracadabra.
407</p>
408
135<pre caption="Installing ALSA Drivers"> 409<pre caption="Installing alsa-driver">
136# <i>emerge alsa-driver</i> 410# <i>emerge alsa-driver</i>
137</pre> 411</pre>
138 412
139<impo> 413<impo>
140Whenever you (re)compile your kernel sources, chances are that the ALSA drivers 414Please 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 415kernel (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 416easier, you may want to emerge the <c>module-rebuild</c> package, which will
143rebooted into the new kernel. 417keep track of module packages and rebuild them for you. First run
418<c>module-rebuild populate</c> to create the list, and then after every kernel
419(re)compile, you just run <c>module-rebuild rebuild</c>, and your external
420modules will be rebuilt.
144</impo> 421</impo>
145 422
146</body> 423</body>
147</section> 424</section>
425</chapter>
426
427<chapter>
428<title>Configuring/Testing ALSA</title>
148<section id="alsa-utils"> 429<section id="alsa-utilities">
149<title>Installing the ALSA Utils</title> 430<title>ALSA Utilities</title>
150<body> 431<body>
151 432
152<p>
153If you want backwards compatibility with OSS, you need to install
154<c>alsa-oss</c>:
155</p> 433<p>
156 434<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"> 435programs that are highly useful, including the ALSA Initscripts. Hence we
158# <i>emerge alsa-oss</i> 436strongly recommend that you install <c>alsa-utils</c>
159</pre>
160
161<p> 437</p>
162Now install the ALSA Utils on your system (this is mandatory):
163</p>
164 438
165<pre caption="Installing ALSA Utils"> 439<pre caption="Install alsa-utils">
166# <i>emerge alsa-utils</i> 440# <i>emerge alsa-utils</i>
167</pre> 441</pre>
168 442
443<note>
444If you activated ALSA in your <uri link="#kernel">kernel</uri> <e>and</e> did
445not compile ALSA as modules, please proceed to the
446<uri link="#initscript">ALSA Initscript</uri> section. The rest of you need
447to configure ALSA. This is made very easy by the existence of the
448<c>alsaconf</c> tool provided by <c>alsa-utils</c>.
449</note>
450
451</body>
452</section>
453<section id="alsa-config">
454<title>Configuration</title>
455<body>
456
457<p>
458Recent versions of <c>udev</c> (<c>>=udev-103</c>) provide some degree of
459kernel-level autoconfiguration of your sound card. If possible, try to rely on
460just letting your kernel automatically setup your sound card for you. Otherwise,
461use <c>alsaconf</c> to configure your card, as shown below.
169<p> 462</p>
170Now that the utils are installed, it is time to configure ALSA... 463
464<note>
465Please shut down any programs that <e>might</e> access the sound card while
466running <c>alsaconf</c>.
467</note>
468
469<p>
470Another way to configure your sound card is to run <c>alsaconf</c>. Just type
471<c>alsaconf</c> in a shell as root.
472</p>
473
474<pre caption="Invoking alsaconf">
475# <i>alsaconf</i>
476</pre>
477
478<p>
479You will now see a neat menu guided interface that will automatically probe
480your devices and try to find out your sound card. You will be asked to pick
481your sound card from a list. Once that's done, it will ask you permission to
482automatically make required changes to <path>/etc/modules.d/alsa</path>.
483It will then adjust your volume settings to optimum levels, run
484<c>update-modules</c> and start the <path>/etc/init.d/alsasound</path> service.
485Once <c>alsaconf</c> exits, you can proceed with setting up the ALSA
486initscript.
487</p>
488
489</body>
490</section>
491<section id="initscript">
492<title>ALSA Initscript</title>
493<body>
494
495<p>
496We're now almost all setup. Whichever method you chose to install ALSA, you'll
497need to have something load your modules or initialize ALSA and restore your
498volume settings when your system comes up. The ALSA Initscript handles all of
499this for you and is called <c>alsasound</c>. Add it to the boot runlevel.
500</p>
501
502<pre caption="Adding ALSA to the boot runlevel">
503# <i>rc-update add alsasound boot</i>
504 * alsasound added to runlevel boot
505 * rc-update complete.
506</pre>
507
508<p>
509Next, just check the <path>/etc/conf.d/alsasound</path> file and ensure that
510SAVE_ON_STOP variable is set to yes. This saves your sound settings when you
511shutdown your system.
512</p>
513
514</body>
515</section>
516<section>
517<title>Audio Group</title>
518<body>
519
520<p>
521Before we move on to testing, there's one last <e>important</e> thing that needs
522to be setup. Rule of thumb in a *nix OS: Do not run as root unless needed.
523This applies here as well ;) How? Well, most of the times you should be logged
524in as a user and would like to listen to music or access your soundcard. For
525that to happen, you need to be in the "audio" group. At this point, we'll add
526users to the audio group, so that they won't have any issues when they want to
527access sound devices. We'll use <c>gpasswd</c> here and you need to be logged in
528as root for this to work.
529</p>
530
531<pre caption="Adding users to the audio group">
532<comment>(Substitute &lt;username&gt; with your user)</comment>
533# <i>gpasswd -a &lt;username&gt; audio </i>
534Adding user &lt;username&gt; to group audio
535</pre>
536
537</body>
538</section>
539<section>
540<title>Volume Check!</title>
541<body>
542
543<p>
544We've completed all the setups and prerequisites, so let's fire up ALSA. If
545you ran <c>alsaconf</c>, you can skip this step, since <c>alsaconf</c> already
546does this for you.
547</p>
548
549<pre caption="Start the service">
550# <i>/etc/init.d/alsasound start</i>
551</pre>
552
553<p>
554Now that the required things have been taken care of, we need to check up on
555the volume as in certain cases, it is muted. We use <c>alsamixer</c> for this
556purpose.
557</p>
558
559<pre caption="Starting alsamixer">
560<comment>(Opens up a console program. Only required settings are shown)</comment>
561# <i>alsamixer</i>
562</pre>
563
564<impo>
565If you have issues starting up <c>alsamixer</c> and get errors such as
566alsamixer: function snd_ctl_open failed for default: No such file or directory,
567this is usually an issue with udev setting up the devices. Run <c>killall
568udevd; udevstart</c> to reload <path>/dev</path> entries and fire up
569<c>alsamixer</c>. It should solve the issue.
570</impo>
571
572<p>
573This is how the ALSA Mixer <e>might</e> look the first time you open it. Pay
574attention to the Master and PCM channels which both have an MM below them.
575That means they are muted. If you try to play anything with <c>alsamixer</c>
576in this state, you will not hear anything on your speakers.
577</p>
578
579<figure link="/images/docs/alsa-mixermuted.png" short="AlsaMixer Muted" caption="The Alsa Mixer Main Window, Muted"/>
580
581<p>
582Now, we shall unmute the channels, and set volume levels as needed.
583</p>
584
585<warn>
586Both Master <e>and</e> PCM need to be unmuted and set to audible volume levels
587if you want to hear some output on your speakers.
588</warn>
589
590<ul>
591 <li>
592 To move between channels, use your left and right arrow keys. (&lt;-
593 &amp; -&gt;)
594 </li>
595 <li>
596 To toggle mute, move to the specific channel, for example Master and press
597 the <e>m</e> key on the keyboard.
598 </li>
599 <li>
600 To increase and decrease the volume levels, use the up and down arrow keys
601 respectively.
602 </li>
603</ul>
604
605<note>
606Be careful when setting your Bass and Treble values. 50 is usually a good
607number for both. Extremely high values of Bass may cause <e>jarring</e>
608on speakers that are not designed to handle them.
609</note>
610
611<p>
612After you're all done, your ALSA Mixer should look similar to the one below.
613Note the 00 instead of the MM and also the volume levels for some optimum
614settings.
615</p>
616
617<figure link="/images/docs/alsa-mixerunmuted.png" short="AlsaMixer Unmuted" caption="Alsa Mixer ready to roll"/>
618
619</body>
620</section>
621<section>
622<title>Sound Check!</title>
623<body>
624
625<p>
626Finally. Some music. If everything above is perfect, you should now be able to
627listen to some good music. A quick way to test is to use a command line tool
628like <c>media-sound/madplay</c>. You could also use something more well known
629like <c>mpg123</c>. If you are an ogg fan, you could use <c>ogg123</c> provided
630by <c>media-sound/vorbis-tools</c>. Use any player you are comfortable with. As
631always, <c>emerge</c> what you need.
632</p>
633
634<pre caption="Getting the software">
635<comment>(Install the applications you want)</comment>
636# <i>emerge madplay mpg123</i>
637<comment>(To play .ogg files)</comment>
638# <i>emerge vorbis-tools</i>
639</pre>
640
641<p>
642And then play your favorite sound track...
643</p>
644
645<pre caption="Playing Music">
646# <i>madplay -v /mnt/shyam/Music/Paul\ Oakenfold\ -\ Dread\ Rock.mp3</i>
647MPEG Audio Decoder 0.15.2 (beta) - Copyright (C) 2000-2004 Robert Leslie et al.
648 Title: Dread Rock
649 Artist: Paul Oakenfold
650 Album: Matrix Reloaded
651 Year: 2003
652 Genre: Soundtrack
653 Soundtrack
654 00:04:19 Layer III, 160 kbps, 44100 Hz, joint stereo (MS), no CRC
655
656# <i>ogg123 Paul\ Oakenfold\ -\ Dread\ Rock.ogg</i>
657Audio Device: Advanced Linux Sound Architecture (ALSA) output
658
659Playing: Paul Oakenfold - Dread Rock.ogg
660Ogg Vorbis stream: 2 channel, 44100 Hz
661Genre: Soundtrack
662Transcoded: mp3;160
663Title: Dread Rock
664Artist: Paul Oakenfold
665Date: 2003
666Album: Matrix Reloaded
667Time: 00:11.31 [04:28.75] of 04:40.06 (200.6 kbps) Output Buffer 96.9%
668</pre>
669
670</body>
671</section>
672<section>
673<title>ALSA and USE</title>
674<body>
675
676<p>
677You can now add the <c>alsa</c> use flag to <path>/etc/make.conf</path> to
678ensure that your applications that support ALSA get built with it. Some
679architectures like x86 and amd64 have the flag enabled by default.
680</p>
681
682</body>
683</section>
684<section>
685<title>Issues?</title>
686<body>
687
688<p>
689If for some reason you're unable to hear sound, the first thing to do would
690be to check your <uri link="#doc_chap3_pre6">alsamixer</uri> settings. 80% of
691the issues lie with muted channels or low volume. Also check your Window
692Manager's sound applet and verify that volumes are set to audible levels.
693</p>
694
695<p>
696<path>/proc</path> is your friend. And in this case, <path>/proc/asound</path>
697is your best friend. We shall just take a short look at how much info is made
698available to us there.
699</p>
700
701<pre caption="Fun with /proc/asound">
702<comment>(First and foremost, if /proc/asound/cards shows your card, ALSA has
703picked up your sound card fine.)</comment>
704# <i>cat /proc/asound/cards</i>
7050 [Live ]: EMU10K1 - Sound Blaster Live!
706 Sound Blaster Live! (rev.6, serial:0x80271102) at 0xb800, irq 11
707
708<comment>(This displays the current running ALSA version)</comment>
709# <i>cat /proc/asound/version</i>
710Advanced Linux Sound Architecture Driver Version 1.0.8 (Thu Jan 13 09:39:32 2005 UTC).
711
712<comment>(ALSA OSS emulation details)</comment>
713# <i>cat /proc/asound/oss/sndstat</i>
714Sound Driver:3.8.1a-980706 (ALSA v1.0.8 emulation code)
715Kernel: Linux airwolf.zion 2.6.11ac1 #2 Wed May 4 00:35:08 IST 2005 i686
716Config options: 0
717
718Installed drivers:
719Type 10: ALSA emulation
720
721Card config:
722Sound Blaster Live! (rev.6, serial:0x80271102) at 0xb800, irq 11
723
724Audio devices:
7250: EMU10K1 (DUPLEX)
726
727Synth devices: NOT ENABLED IN CONFIG
728
729Midi devices:
7300: EMU10K1 MPU-401 (UART)
731
732Timers:
7337: system timer
734
735Mixers:
7360: SigmaTel STAC9721/23
737</pre>
738
739<p>
740The other most common issue users face is the dreaded "Unknown symbol in module"
741error. An example of the same is shown below.
742</p>
743
744<pre caption="Unknown Symbol in module error">
745# <i>/etc/init.d/alsasound start</i>
746 * Loading ALSA modules ...
747 * Loading: snd-card-0 ... [ ok ]
748 * Loading: snd-pcm-oss ...
749WARNING: Error inserting snd_mixer_oss
750(/lib/modules/2.6.12-gentoo-r6/kernel/sound/core/oss/snd-mixer-oss.ko): Unknown
751symbol in module, or unknown parameter (see dmesg) FATAL: Error inserting
752snd_pcm_oss
753(/lib/modules/2.6.12-gentoo-r6/kernel/sound/core/oss/snd-pcm-oss.ko): Unknown
754symbol in module, or unknown parameter (see dmesg)
755 [ !! ]
756 * Loading: snd-mixer-oss ...
757FATAL: Error inserting snd_mixer_oss
758(/lib/modules/2.6.12-gentoo-r6/kernel/sound/core/oss/snd-mixer-oss.ko): Unknown
759symbol in module, or unknown parameter (see dmesg)
760 [ !! ]
761 * Loading: snd-seq ... [ ok ]
762 * Loading: snd-emu10k1-synth ... [ ok ]
763 * Loading: snd-seq-midi ... [ ok ]
764 * Restoring Mixer Levels ... [ ok ]
765</pre>
766
767<p>
768And when you take a look at <c>dmesg</c> as suggested, you're quite likely to
769see:
770</p>
771
772<pre caption="dmesg output">
773<comment>(Only relevant portions are shown below)</comment>
774# <i>dmesg | less</i>
775ACPI: PCI Interrupt 0000:02:06.0[A] -> Link [APC3] -> GSI 18 (level, low) -> IRQ 209
776snd_mixer_oss: Unknown symbol snd_unregister_oss_device
777snd_mixer_oss: Unknown symbol snd_register_oss_device
778snd_mixer_oss: Unknown symbol snd_mixer_oss_notify_callback
779snd_mixer_oss: Unknown symbol snd_oss_info_register
780snd_pcm_oss: Unknown symbol snd_unregister_oss_device
781snd_pcm_oss: Unknown symbol snd_register_oss_device
782snd_pcm_oss: Unknown symbol snd_mixer_oss_ioctl_card
783snd_pcm_oss: Unknown symbol snd_oss_info_register
784snd_mixer_oss: Unknown symbol snd_unregister_oss_device
785snd_mixer_oss: Unknown symbol snd_register_oss_device
786snd_mixer_oss: Unknown symbol snd_mixer_oss_notify_callback
787snd_mixer_oss: Unknown symbol snd_oss_info_register
788</pre>
789
790<p>
791The above issue is caused when you switch from <c>alsa-driver</c> to in-kernel
792ALSA because when you unmerge <c>alsa-driver</c> the module files are config
793protected and hence get left behind. So, when you switch to in-kernel
794drivers, running <c>modprobe</c> gives you a mix of <c>alsa-driver</c> and
795in-kernel modules thus causing the above errors.
796</p>
797
798<p>
799The solution is quite easy. We just need to manually remove the problem causing
800directory after you unmerge <c>alsa-driver</c>. Be sure to remove the correct
801kernel version and not the current one!
802</p>
803
804<pre caption="Removing the alsa-driver modules">
805# <i>rm -rf /lib/modules/$(uname -r)/alsa-driver</i>
806</pre>
807
808<p>
809Another reason for error messages similar to the ones above could be a file in
810<path>/etc/modules.d</path> supplying a <c>device_mode</c> parameter when it
811isn't required. Confirm that this is indeed the issue and find out which file
812is the culprit.
813</p>
814
815<pre caption="Confirming and searching for device_mode">
816<comment>(Check dmesg to confirm)</comment>
817# <i>dmesg | grep device_mode</i>
818snd: Unknown parameter `device_mode'
819<comment>(Now, to get to the source of the issue)</comment>
820# <i>grep device_mode /etc/modules.d/*</i>
821</pre>
822
823<p>
824Usually it is a file called <path>alsa</path> with the line <c>options snd
825device_mode=0666</c>. Remove this line and restart the alsasound service and
826that should take care of this issue.
171</p> 827</p>
172 828
173</body> 829</body>
174</section> 830</section>
175</chapter> 831</chapter>
832
176<chapter> 833<chapter>
177<title>Configuring ALSA</title> 834<title>Other things ALSA</title>
178<section> 835<section id="midi">
179<title>Automatically Loading the Kernel Modules</title> 836<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> 837<body>
207</section>
208<section>
209<title>Verifying the Device Files</title>
210<body>
211 838
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> 839<p>
217 840First, check to make sure that you enabled the <c>midi</c> USE flag in
218<pre caption="/etc/devfsd.conf"> 841<path>/etc/make.conf</path>. If you didn't, go ahead and add it now. You will
219# ALSA/OSS stuff 842also need to re-emerge any ALSA packages that use the <c>midi</c> flag, such as
220# Comment/change these if you want to change the permissions on 843<c>alsa-lib</c>, <c>alsa-utils</c>, and <c>alsa-driver</c>.
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> 844</p>
237To activate ALSA support at boot, add the <c>alsasound</c> init script to the 845
238boot runlevel:
239</p> 846<p>
240 847If your sound card is one of those that come with on-board MIDI synthesizers
241<pre caption="Adding alsasound to the boot runlevel"> 848and you would like to listen to some .mid files, you have to install
242# <i>rc-update add alsasound boot</i> 849<c>awesfx</c> which is basically a set of utilities for controlling the AWE32
243# <i>/etc/init.d/alsasound start</i> 850driver. We need to install it first. If you don't have a hardware synthesizer,
244</pre> 851you can use a virtual one. Please see the section on
245 852<uri link="#vsynth">Virtual Synthesizers</uri> for more information.
246</body>
247</section>
248<section>
249<title>Unmute the Channels</title>
250<body>
251
252<p> 853</p>
253By default, all sound channels are muted. To fix this, run <c>amixer</c>:
254</p>
255 854
256<pre caption="Running amixer">
257# <i>amixer</i>
258</pre>
259
260<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
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"> 855<pre caption="Installing awesfx">
304# <i>emerge awesfx</i> 856# <i>emerge awesfx</i>
305</pre> 857</pre>
306 858
307<p> 859<note>
308If you have a collection of sound fonts somewhere, place them in 860You 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 861CD or a Windows installation into <path>/usr/share/sounds/sf2/</path>. For
310called <path>8MBGMSFX.SF2</path> or <path>CT4GMSFX.SF2</path>. 862example a sound font file for the Creative SBLive! card would be 8MBGMSFX.SF2.
863</note>
864
311</p> 865<p>
312 866After copying over the Soundfont files, we can then play a midi file as shown.
867You can also add the <c>asfxload</c> command to
868<path>/etc/conf.d/local.start</path>, so that the sound font is loaded
869every time the system starts up.
313<p> 870</p>
314After copying over the sound font, select them using <c>sfxload</c>:
315</p>
316 871
872<note>
873<path>/mnt</path> paths mentioned in the code listing(s) below will <e>not</e>
874be the same in your machine. They are just an example. Please be careful to
875change the path to suit your machine.
876</note>
877
317<pre caption="Loading the sound font"> 878<pre caption="Loading Soundfonts">
879<comment>(First, copy the Soundfont)</comment>
880# <i>cp /mnt/win2k/Program\ Files/CreativeSBLive2k/SFBank/8MBGMSFX.SF2 /usr/share/sounds/sf2/</i>
881<comment>(Or get it from your SoundBlaster CD)</comment>
882# <i>cp /mnt/cdrom/AUDIO/ENGLISH/SFBANK/8MBGMSFX.SF2 /usr/share/sounds/sf2/</i>
883<comment>(We load the specific Soundfont)</comment>
318# <i>sfxload /usr/share/sfbank/8MBGMSFX.SF2</i> 884# <i>asfxload /usr/share/sounds/sf2/8MBGMSFX.SF2</i>
319</pre> 885</pre>
320 886
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> 887<p>
325 888You can now play midi files using a program like <c>aplaymidi</c>. Run
889<c>aplaymidi -l</c> to get a list of available ports and then pick one
890to play the file on.
326<p> 891</p>
327If you can't find soundfonts on your driver CD you can download some online from 892
328<uri>http://www.parabola.demon.co.uk/alsa/awe64.html</uri>. 893<pre caption="Playing MIDI">
894<comment>(Check open ports)</comment>
895# <i>aplaymidi -l</i>
896 Port Client name Port name
897 64:0 EMU10K1 MPU-401 (UART) EMU10K1 MPU-401 (UART)
898 65:0 Emu10k1 WaveTable Emu10k1 Port 0
899 65:1 Emu10k1 WaveTable Emu10k1 Port 1
900 65:2 Emu10k1 WaveTable Emu10k1 Port 2
901 65:3 Emu10k1 WaveTable Emu10k1 Port 3
902<comment>(Pick a port, and play a mid file)</comment>
903# <i> aplaymidi --port=65:0 /mnt/shyam/music/midi/mi2.mid</i>
329</p> 904</pre>
330 905
331</body> 906</body>
332</section>
333<section> 907</section>
908<section id="vsynth">
334<title>Timidity++ Virtual Synthesizer</title> 909<title>Virtual Synthesizers</title>
335<body> 910<body>
336 911
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> 912<p>
913If your sound card lacks a hardware synthesizer, you could use a virtual one
914like <c>timidity++</c>. Installation is a breeze.
915</p>
342 916
343<pre caption="Installing Timidity++"> 917<pre caption="Installing timidity++">
344# <i>emerge timidity++</i> 918# <i>emerge timidity++</i>
345</pre> 919</pre>
346 920
347<p> 921<p>
348A sample configuration file will be installed for you in 922For 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 923install some sound font packages for you. There are a few other font packages
350timidity++ configuration setup yet, you can just use this one. 924available in Portage, such as <c>timidity-freepats</c> and
351</p> 925<c>timidity-eawpatches</c>. You can have multiple sound font configurations
352 926installed, and you can place your own in <path>/usr/share/timidity/</path>. To
353<pre caption="Using the default Timidity++ configuration file"> 927switch between different timidity configurations, you should use
354# <i>cp /usr/share/timidity/config/timidity.cfg /usr/share/timidity</i> 928<c>eselect</c>.
355</pre>
356
357<p> 929</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>
361 930
362<pre caption="Installing timidity-eawpatches"> 931<pre caption="Changing configurations">
932# <i>eselect timidity list</i>
363# <i>emerge timidity-eawpatches</i> 933# <i>eselect timidity set eawpatches</i>
364</pre> 934</pre>
365 935
366<p> 936<p>
367Don't forget to add <c>timidity</c> to the default runlevel. 937Don't forget to add <c>timidity</c> to the default runlevel.
368</p> 938</p>
370<pre caption="Adding timidity to the default runlevel"> 940<pre caption="Adding timidity to the default runlevel">
371# <i>rc-update add timidity default</i> 941# <i>rc-update add timidity default</i>
372# <i>/etc/init.d/timidity start</i> 942# <i>/etc/init.d/timidity start</i>
373</pre> 943</pre>
374 944
945<p>
946You can now try out <uri link="#doc_chap4_pre3">Playing MIDI</uri> files.
947</p>
948
375</body> 949</body>
376</section>
377<section> 950</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> 951<section>
413<title>Tools and Firmware</title> 952<title>Tools and Firmware</title>
414<body> 953<body>
415 954
416<p> 955<p>
417Some specific sound cards can benefit from certain tools provided by the 956Some 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 957<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 958a 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> 959</p>
430 960
431<pre caption="Installing ALSA Tools"> 961<pre caption="Installing ALSA Tools">
432# <i>emerge alsa-tools</i> 962# <i>emerge alsa-tools</i>
433</pre> 963</pre>
434 964
435</body> 965</body>
436</section> 966</section>
437<section> 967<section>
438<title>Activating Joystick Support</title> 968<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> 969<body>
482</section> 970
971<p>
972You can have more than one sound card in your system simultaneously, provided
973that you have built ALSA as modules in your kernel (or have installed
974<c>alsa-driver</c> instead). You just need to specify which should be started
975first in <path>/etc/modules.d/alsa</path>. Your cards are identified by their
976driver names inside this file. 0 is the first card, 1 is the second, and so on.
977Here's an example for a system with two sound cards.
978</p>
979
980<pre caption="Two sound cards in /etc/modules.d/alsa">
981options snd-emu10k1 index=0
982options snd-via82xx index=1
983</pre>
984
985<p>
986Or, if you have two cards that use the same driver, you specify them on the same
987line, using comma-separated numbers. Here's an example for a system with three
988sound cards, two of which are the same Intel High Definition Audio card.
989</p>
990
991<pre caption="Multiple sound cards in /etc/modules.d/alsa">
992options snd-ymfpci index=0
993options snd-hda-intel index=1,2
994</pre>
995
996</body>
483<section> 997</section>
998<section>
999<title>Plugins</title>
1000<body>
1001
1002<p>
1003You may want to install some plugins for extra functionality.
1004<c>alsa-plugins</c> is a collection of useful plugins, which include: PulseAudio
1005output, a sample rate converter, jack (a low-latency audio server), and an
1006encoder that lets you output 6-channel audio through digital S/PDIF connections
1007(both optical and coaxial). You can choose which of its plugins you want
1008installed by adding their USE flags to <path>/etc/portage/package.use</path>.
1009</p>
1010
1011<pre caption="Installing alsa-plugins">
1012# <i>emerge -avt alsa-plugins</i>
1013</pre>
1014
1015</body>
1016</section>
1017<section>
1018<title>A big thank you to...</title>
1019<body>
1020
1021<p>
1022Everyone who contributed to the earlier version of the Gentoo ALSA Guide:
1023Vincent Verleye, Grant Goodyear, Arcady Genkin, Jeremy Huddleston,
1024John P. Davis, Sven Vermeulen, Benny Chuang, Tiemo Kieft and Erwin.
1025</p>
1026
1027</body>
1028</section>
1029<section>
484<title>Resources</title> 1030<title>References</title>
485<body> 1031<body>
486 1032
487<ul> 1033<ul>
488 <li><uri link="http://www.alsa-project.org">The ALSA Project</uri></li> 1034 <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> 1035 <li><uri link="http://linux-sound.org">Linux Sound/MIDI Software</uri></li>
491</ul> 1036</ul>
492 1037
493</body> 1038</body>
494</section> 1039</section>

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