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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 1.86 2012/05/27 18:52:32 ago Exp $ -->
3
2<!DOCTYPE guide SYSTEM "/dtd/guide.dtd"> 4<!DOCTYPE guide SYSTEM "/dtd/guide.dtd">
3 5
4<guide link = "/doc/en/alsa-guide.xml"> 6<guide>
5<title>Gentoo Linux ALSA Guide</title> 7<title>Gentoo Linux ALSA Guide</title>
6<author title="Author"><mail link="zu@pandora.be"> 8
7 Vincent Verleye</mail> 9<author title="Author">
10 <mail link="fox2mike@gentoo.org">Shyam Mani</mail>
8</author> 11</author>
9<author title="Author"><mail link="g2boojum@gentoo.org"> 12<author title="Author">
10 Grant Goodyear</mail> 13 <mail link="nightmorph@gentoo.org">Joshua Saddler</mail>
11</author> 14</author>
12<author title="Author"><mail link="agenkin@gentoo.org"> 15<author title="Contributor">
13 Arcady Genkin</mail> 16 <mail link="flameeyes@gentoo.org">Diego Pettenò</mail>
14</author> 17</author>
15<author title="Editor"><mail link="zhen@gentoo.org">
16 John P. Davis</mail>
17</author>
18<author title="Editor"><mail link="swift@gentoo.org">
19 Sven Vermeulen</mail>
20</author>
21<author title="Editor"><mail link="bennyc@gentoo.org">
22 Benny Chuang</mail>
23</author>
24<author title="Editor"><mail link="blubber@gentoo.org">
25 Tiemo Kieft</mail>
26</author>
27 18
19<abstract>
20This document helps a user setup ALSA on Gentoo Linux.
21</abstract>
22
23<!-- The content of this document is licensed under the CC-BY-SA license -->
24<!-- See http://creativecommons.org/licenses/by-sa/2.5 -->
28<license/> 25<license/>
29 26
30<abstract>
31This guide will show you how to set up the Advanced Linux Sound Architecture (ALSA) on Gentoo Linux.
32In addition to the Gentoo Linux Desktop Configuration Guide, this guide is supposed to give you more information on this subject. </abstract>
33
34<version>1.3.3</version> 27<version>3.1</version>
35<date>October 9, 2003</date> 28<date>2012-05-27</date>
36 29
37<chapter> 30<chapter>
38<title>Introduction</title> 31<title>Introduction</title>
39<section> 32<section>
40 <title>What is ALSA?</title> 33<title>What is ALSA?</title>
34<body>
35
36<p>
37ALSA, which stands for <e>Advanced Linux Sound Architecture</e>, provides audio
38and MIDI (<e>Musical Instrument Digital Interface</e>) functionality to the
39Linux operating system. ALSA is the default sound subsystem in the 3.x and 2.6
40kernels, thereby replacing OSS (<e>Open Sound System</e>), which was used in
41the 2.4 kernels.
42</p>
43
44<p>
45ALSA's main features include efficient support for all types of audio
46interfaces ranging from consumer sound cards to professional sound
47equipment, fully modularized drivers, SMP and thread safety, backward
48compatibility with OSS and a user-space library <c>alsa-lib</c> to make
49application development a breeze.
50</p>
51
41<body> 52</body>
42<p> 53</section>
43The Advanced Linux Sound Architecture (ALSA) is a project to improve the Linux sound subsystem by rewriting 54</chapter>
44large chunks of it. 55
45It is anticipated that ALSA will make it into Linux kernel 2.6.x (or 3.x.x -- whichever comes first) as it becomes ready. 56<chapter>
57<title>Installing ALSA</title>
58<section id="lspci">
59<title>Before you proceed</title>
60<body>
61
46</p> 62<p>
47 63First, you need to know what drivers your sound card uses. In most cases, sound
64cards (onboard and otherwise) are PCI based and <c>lspci</c> will help you in
65digging out the required information. Please <c>emerge sys-apps/pciutils</c> to
66get <c>lspci</c>, if you don't have it installed already. In case you have a USB
67sound card, <c>lsusb</c> from <c>sys-apps/usbutils</c> <e>might</e> be of help.
68For ISA cards, try using <c>sys-apps/isapnptools</c>. Also, the following pages
69<e>may</e> help users with ISA based sound cards:
48<p> 70</p>
49ALSA provides audio and MIDI functionality for Linux. 71
50</p> 72<ul>
51 73 <li>
52<p> 74 <uri link="http://www.roestock.demon.co.uk/isapnptools/">The ISAPNPTOOLS
53Quoted from <uri>http://www.alsa-project.org</uri>, ALSA has the following features: 75 Page</uri>
54<ul><li> Efficient support for all types of audio interfaces, from consumer soundcards to professional multichannel audio interfaces.</li> 76 </li>
55 <li> Fully modularized sound drivers.</li> 77 <li>
56 <li> SMP and thread-safe design.</li> 78 <uri link="http://www2.linuxjournal.com/article/3269">LinuxJournal PnP
57 <li> User space library (alsa-lib) to simplify application programming and provide higher level functionality.</li> 79 Article</uri>
58 <li> Support for the older OSS API, providing binary compatibility for most OSS programs.</li> 80 </li>
81 <li>
82 <uri link="http://www.tldp.org/HOWTO/Sound-HOWTO/x320.html">TLDP Sound
83 HowTo</uri>
84 </li>
59</ul> 85</ul>
60There's lots more to ALSA however, like support for Full Duplex playback and recording, multiple soundcard support, 86
61hardware mixing of streams, extensive mixer capabilities (to support advanced features of new soundcards), ... 87<note>
88For ease of use/explanation, we assume the user has a PCI based sound card for
89the remainder of this guide.
90</note>
91
62</p> 92<p>
93We now proceed to find out details about the sound card.
94</p>
95
96<pre caption="Soundcard Details">
97# <i>lspci -v | grep -i audio</i>
980000:00:0a.0 Multimedia audio controller: Creative Labs SB Live! EMU10k1 (rev 06)
99</pre>
100
101<p>
102We now know that the sound card on the machine is a Sound Blaster Live! and the
103card manufacturer is Creative Labs. Head over to the <uri
104link="http://bugtrack.alsa-project.org/main/index.php/Matrix:Main">ALSA
105Soundcard Matrix</uri> page and select Creative Labs from the list. You will
106be taken to the Creative Labs matrix page where you can see that the SB Live!
107uses the <c>emu10k1</c> module. That is the information we need for now. If
108you are interested in detailed information, you can click on the link next to
109the "Details" and that will take you to the <c>emu10k1</c> specific page.
110</p>
111
112<p>
113If you intend to use MIDI, then you should add <c>midi</c> to your USE flags in
114<path>/etc/make.conf</path> before emerging any ALSA packages. Later in the
115guide, we will show you how to set up <uri link="#midi">MIDI support</uri>.
116</p>
117
63</body> 118</body>
64</section>
65<section> 119</section>
66 <title>Why use ALSA?</title> 120<section id="kernel">
67<body> 121<title>Configuring the kernel</title>
68<p>
69If your soundcard is supported by the Linux kernel sound system or the commercial OSS/4Front sound driver system,
70which can be found in all 2.4.x Linux kernels, you could just aswell build <e>those modules</e> for use with your soundcard.
71If you want this, just read through the <uri link="http://www.tldp.org/HOWTO/Sound-HOWTO/index.html">Linux Sound HOWTO</uri>.
72</p>
73<p>
74However, those OSS/4Front drivers have some limitations -- being commercial is one.
75ALSA is an attempt to go beyond these limitations and to do so in an open source fashion.
76ALSA is a fully GPL and LGPL'ed sound driver system, that provides a professional quality system for recording, playback,
77and MIDI sequencing.
78</p>
79</body> 122<body>
80</section> 123
81<section> 124<note>
82 <title>What cards does ALSA support?</title> 125Since the 2005.0 release, Gentoo Linux uses 2.6 as the default kernel. Please
83<body> 126check that your kernel is a 2.6 series kernel. This method will <e>not</e> work
84<p> 127on a 2.4 kernel.
85ALSA tries to support as many (new) cards as possible by providing open-source drivers. 128</note>
86However, some vendors may provide binary-only packages. 129
87</p> 130<p>
88<p>To know if your card is supported, you can find a Soundcard Matrix of supported and not-supported cards here: 131Let us now configure the kernel to enable ALSA.
89<uri>http://www.alsa-project.org/alsa-doc/</uri>. 132</p>
133
134<impo>
135<c>genkernel</c> users should now run <c>genkernel --menuconfig all</c> and
136then follow the instructions in <uri link="#doc_chap2_pre3">Kernel Options for
137ALSA</uri>.
138</impo>
139
140<pre caption="Heading over to the source">
141# <i>cd /usr/src/linux</i>
142# <i>make menuconfig</i>
143</pre>
144
145<note>
146The above example assumes that <path>/usr/src/linux</path> symlink points to
147the kernel sources you want to use. Please ensure the same before proceeding.
148</note>
149
90</p> 150<p>
151Now we will look at some of the options we will have to enable in the 2.6
152kernel to ensure proper ALSA support for our sound card.
153</p>
154
155<p>
156Please note that for ease of use, all examples show ALSA built as modules. It
157is advisable to follow the same as it then allows the use of <c>alsaconf</c>
158which is a boon when you want to configure your card. Please do <e>not</e> skip
159the <uri link="#alsa-config">Configuration</uri> section of this document. If
160you still like to have options built-in, ensure that you make changes to your
161config accordingly.
162</p>
163
164<pre caption="Kernel Options for ALSA">
165Device Drivers ---&gt;
166 Sound ---&gt;
167
168<comment>(This needs to be enabled)</comment>
169&lt;M&gt; Sound card support
170
171<comment>(Make sure OSS is disabled)</comment>
172Open Sound System ---&gt;
173 &lt; &gt; Open Sound System (DEPRECATED)
174
175<comment>(Move one step back and enter ALSA)</comment>
176Advanced Linux Sound Architecture ---&gt;
177 &lt;M&gt; Advanced Linux Sound Architecture
178 <comment>(Select this if you want MIDI sequencing and routing)</comment>
179 &lt;M&gt; Sequencer support
180 <comment>(Old style /dev/mixer* and /dev/dsp* support. Recommended.)</comment>
181 &lt;M&gt; OSS Mixer API
182 &lt;M&gt; OSS PCM (digital audio) API
183
184<comment>(You now have a choice of devices to enable support for. Generally,
185you will have one type of device and not more. If you have more than one
186sound card, please enable them all here.)</comment>
187
188<comment>(Mostly for testing and development purposes, not needed for normal
189users unless you know what you are doing.)</comment>
190Generic devices ---&gt;
191
192<comment>(For ISA Sound cards)</comment>
193ISA devices ---&gt;
194<comment>(IF you had the Gravis, you would select this option)</comment>
195 &lt;M&gt; Gravis UltraSound Extreme
196
197<comment>(Move one level back and into PCI devices. Most sound cards today are
198PCI devices)</comment>
199PCI devices ---&gt;
200 <comment>(We now select the emu10k1 driver for our card)</comment>
201 &lt;M&gt; Emu10k1 (SB Live!, Audigy, E-mu APS)
202 <comment>(Or an Intel card would be)</comment>
203 &lt;M&gt; Intel/SiS/nVidia/AMD/ALi AC97 Controller
204 <comment>(Or if you have a VIA Card)</comment>
205 &lt;M&gt; VIA 82C686A/B, 8233/8235 AC97 Controller
206
207<comment>(Move one level back and select in case you have an USB sound card)</comment>
208USB Devices ---&gt;
209</pre>
210
211<p>
212Now that your options are set, you can (re)compile the kernel and ALSA support
213for your card should be functional once you reboot into the new kernel. Don't
214forget to update your GRUB configuration to use the newly built kernel.
215You can now proceed to <uri link="#alsa-utilities">ALSA Utilities</uri> and
216see if everything is working as it should.
217</p>
218
91</body> 219</body>
92</section> 220</section>
93</chapter> 221</chapter>
94 222
95<chapter> 223<chapter>
96<title>Installation</title> 224<title>Configuring/Testing ALSA</title>
97<section> 225<section id="alsa-utilities">
98<title>Gentoo USE flags</title> 226<title>ALSA Utilities</title>
99<body>
100
101<p>
102To compile programs with ALSA-support, be sure to add <e>alsa</e> to
103your USE-variable. However, several tools don't support alsa yet, and
104require OSS. ALSA provides OSS-emulation if you define <e>oss</e> in your
105USE-variable before you start.
106</p>
107
108</body> 227<body>
109</section>
110 228
111<section>
112 <title>Kernel modules</title>
113<body>
114<p>
115Since we're still using 2.4.x kernel sources, we'll have to compile kernel modules and ALSA modules separately. People who are using a 2.5.x kernel can do this from within their kernel configuration, since the ALSA modules are included in the kernel sources and should be built there.
116</p> 229<p>
230<c>alsa-utils</c> forms an integral part of ALSA as it has a truckload of
231programs that are highly useful, including the ALSA Initscripts. Hence we
232strongly recommend that you install <c>alsa-utils</c>
117<p> 233</p>
118First we'll make sure that our kernel configuration is ready for use with ALSA. 234
119All you need in your kernel configuration is having Sound Card Support set to be built as a module (M). 235<pre caption="Install alsa-utils">
120This will build <c>soundcore.o</c>. 236# <i>emerge alsa-utils</i>
121</p> 237</pre>
122<p> 238
123<note> 239<note>
124Possibly, this will also work when you built Sound Card Support in the kernel (Y) instead of building it as a module (M). 240If you did <e>not</e> compile ALSA as modules, please proceed to the <uri
125However, the official ALSA documentation suggests building it as a module, since ALSA will try loading it. 241link="#initscript">ALSA Initscript</uri> section. The rest of you need to
242configure ALSA. This is made very easy by the existence of the <c>alsaconf</c>
243tool provided by <c>alsa-utils</c>.
126</note> 244</note>
245
246</body>
247</section>
248<section id="alsa-config">
249<title>Configuration</title>
250<body>
251
127</p> 252<p>
128<p>If you already have a working kernel configuration, make sure you remove all sound drivers (except for Sound Card Support). 253Recent versions of <c>udev</c> (<c>>=udev-103</c>) provide some degree of
129If you wish to do this without having to reboot, you could do like this: 254kernel-level autoconfiguration of your sound card. If possible, try to rely on
130</p> 255just letting your kernel automatically setup your sound card for you. Otherwise,
131<pre> 256use <c>alsaconf</c> to configure your card, as shown below.
132# <i>cd /usr/src/linux</i>
133# <i>cp .config ~/</i>
134# <i>make mrproper</i>
135# <i>cp ~/.config .</i>
136# <i>make menuconfig</i>
137</pre>
138<p> 257</p>
139Now select <e>Sound Card Support</e> as Module (M) and deselect all other sound drivers. 258
140Exit and say Y to save your kernel configuration. 259<note>
141After that, build the modules: 260Please shut down any programs that <e>might</e> access the sound card while
142</p> 261running <c>alsaconf</c>.
143<pre>
144# <i>make dep clean</i>
145# <i>make modules modules_install</i>
146</pre>
147<p>
148Before installing your new modules, this last line will delete all your previous modules,
149even the ones from a previous ALSA installation.
150</p>
151<p>
152<impo>
153This means, whenever you recompile your kernel later on, you MUST recompile <c>alsa-driver</c>.
154</impo>
155</p>
156<p>
157<note>However, there's no need to reinstall <c>nvidia-kernel</c>, the Nvidia drivers are in a separate directory
158in <path>/lib/modules/*/video</path> and won't get deleted by a <c>make modules modules_install</c>
159</note> 262</note>
263
160</p> 264<p>
161</body> 265To configure your sound card just type <c>alsaconf</c> in a shell as root.
162</section> 266</p>
163 267
268<pre caption="Invoking alsaconf">
269# <i>alsaconf</i>
270</pre>
271
272<p>
273You will now see a neat menu guided interface that will automatically probe
274your devices and try to find out your sound card. You will be asked to pick
275your sound card from a list. Once that's done, it will ask you permission to
276automatically make required changes to <path>/etc/modprobe.d/alsa.conf</path>.
277It will then adjust your volume settings to optimum levels, run
278<c>update-modules</c> and start the <path>/etc/init.d/alsasound</path> service.
279Once <c>alsaconf</c> exits, you can proceed with setting up the ALSA
280initscript.
281</p>
282
283</body>
164<section> 284</section>
165 <title>ALSA modules</title> 285<section id="initscript">
286<title>ALSA Initscript</title>
287<body>
288
289<p>
290We're now almost all setup. Whichever method you chose to install ALSA, you'll
291need to have something load your modules or initialize ALSA and restore your
292volume settings when your system comes up. The ALSA Initscript handles all of
293this for you and is called <c>alsasound</c>. Add it to the boot runlevel.
294</p>
295
296<pre caption="Adding ALSA to the boot runlevel">
297# <i>rc-update add alsasound boot</i>
298 * alsasound added to runlevel boot
299 * rc-update complete.
300</pre>
301
302<p>
303Next, just check the <path>/etc/conf.d/alsasound</path> file and ensure that
304SAVE_ON_STOP variable is set to yes. This saves your sound settings when you
305shutdown your system.
306</p>
307
166<body> 308</body>
309</section>
310<section>
311<title>Audio Group</title>
312<body>
167 313
168<p>
169Now it's time to install the ALSA drivers for your soundcard(s). If your soundcard is PCI, you can find out the name
170and type of your soundcard by looking at the output of /proc/pci.
171</p> 314<p>
315Before we move on to testing, there's one last <e>important</e> thing that needs
316to be setup. Rule of thumb in a *nix OS: Do not run as root unless needed.
317This applies here as well ;) How? Well, most of the times you should be logged
318in as a user and would like to listen to music or access your soundcard. For
319that to happen, you need to be in the "audio" group. At this point, we'll add
320users to the audio group, so that they won't have any issues when they want to
321access sound devices. We'll use <c>gpasswd</c> here and you need to be logged in
322as root for this to work.
323</p>
324
325<pre caption="Adding users to the audio group">
326<comment>(Substitute &lt;username&gt; with your user)</comment>
327# <i>gpasswd -a &lt;username&gt; audio </i>
328Adding user &lt;username&gt; to group audio
172<pre> 329</pre>
173# <i>grep audio /proc/pci</i>
174</pre>
175 330
331</body>
332</section>
333<section>
334<title>Volume Check!</title>
335<body>
176 336
337<p>
338We've completed all the setups and prerequisites, so let's fire up ALSA. If
339you ran <c>alsaconf</c>, you can skip this step, since <c>alsaconf</c> already
340does this for you.
177<p> 341</p>
342
343<pre caption="Start the service">
344# <i>/etc/init.d/alsasound start</i>
345</pre>
346
347<p>
348Now that the required things have been taken care of, we need to check up on
349the volume as in certain cases, it is muted. We use <c>alsamixer</c> for this
350purpose.
351</p>
352
353<pre caption="Starting alsamixer">
354<comment>(Opens up a console program. Only required settings are shown)</comment>
355# <i>alsamixer</i>
356</pre>
357
358<p>
359This is how the ALSA Mixer <e>might</e> look the first time you open it. Pay
360attention to the Master and PCM channels which both have an MM below them.
361That means they are muted. If you try to play anything with <c>alsamixer</c>
362in this state, you will not hear anything on your speakers.
363</p>
364
365<figure link="/images/docs/alsa-mixermuted.png" short="AlsaMixer Muted" caption="The Alsa Mixer Main Window, Muted"/>
366
367<p>
368Now, we shall unmute the channels, and set volume levels as needed.
369</p>
370
178<warn> 371<warn>
179If you had a previous sound setup and there are still non-ALSA sound modules loaded, unload them <e>now</e>. 372Both Master <e>and</e> PCM need to be unmuted and set to audible volume levels
180Check with <c>lsmod</c> and use <c>rmmod</c> to unload all sound-related modules on your system. 373if you want to hear some output on your speakers.
181</warn> 374</warn>
182</p>
183 375
184<p> 376<ul>
185We could simply do an <c>emerge alsa-driver</c> now, this would compile and install <e>all</e> ALSA sound drivers. 377 <li>
186</p> 378 To move between channels, use your left and right arrow keys. (&lt;-
187<p> 379 &amp; -&gt;)
188However, to save some time, lookup the <e>Module Name</e> of your soundcard(s) on the 380 </li>
189<uri link="http://www.alsa-project.org/alsa-doc">ALSA Soundcard Matrix</uri> by following the <e>Details</e> link in the <e>Driver and Docs</e> column in the row of the chipset of your soundcard. 381 <li>
190Mine is <c>snd-emu10k1</c>, since I have an SBlive! soundcard, with the <e>EMU10K1</e> chipset. 382 To toggle mute, move to the specific channel, for example Master and press
191We'll set ALSA_CARDS environment to the value of the module name before emerging (but without the snd prefix), so emerge will only compile the drivers we need. 383 the <e>m</e> key on the keyboard.
192</p> 384 </li>
385 <li>
386 To increase and decrease the volume levels, use the up and down arrow keys
387 respectively.
388 </li>
389</ul>
193 390
194<pre>
195# <i>env ALSA_CARDS='emu10k1' emerge alsa-driver</i>
196</pre>
197<note> 391<note>
198You can also add this value in <path>/etc/make.conf</path>, so when you have to emerge the alsa-driver later on you can just run <c>emerge alsa-driver</c>. 392Be careful when setting your Bass and Treble values. 50 is usually a good
199For example, like this: <c>echo 'ALSA_CARDS="emu10k1"' >> /etc/make.conf</c> 393number for both. Extremely high values of Bass may cause <e>jarring</e>
394on speakers that are not designed to handle them.
200</note> 395</note>
201 396
397<p>
398After you're all done, your ALSA Mixer should look similar to the one below.
399Note the 00 instead of the MM and also the volume levels for some optimum
400settings.
401</p>
402
403<figure link="/images/docs/alsa-mixerunmuted.png" short="AlsaMixer Unmuted" caption="Alsa Mixer ready to roll"/>
404
405</body>
406</section>
407<section>
408<title>Sound Check!</title>
409<body>
410
411<p>
412Finally. Some music. If everything above is perfect, you should now be able to
413listen to some good music. A quick way to test is to use a command line tool
414like <c>media-sound/madplay</c>. You could also use something more well known
415like <c>mpg123</c>. If you are an ogg fan, you could use <c>ogg123</c> provided
416by <c>media-sound/vorbis-tools</c>. Use any player you are comfortable with. As
417always, <c>emerge</c> what you need.
418</p>
419
420<pre caption="Getting the software">
421<comment>(Install the applications you want)</comment>
422# <i>emerge madplay mpg123</i>
423<comment>(To play .ogg files)</comment>
424# <i>emerge vorbis-tools</i>
425</pre>
426
427<p>
428And then play your favorite sound track...
429</p>
430
431<pre caption="Playing Music">
432# <i>madplay -v /mnt/shyam/Music/Paul\ Oakenfold\ -\ Dread\ Rock.mp3</i>
433MPEG Audio Decoder 0.15.2 (beta) - Copyright (C) 2000-2004 Robert Leslie et al.
434 Title: Dread Rock
435 Artist: Paul Oakenfold
436 Album: Matrix Reloaded
437 Year: 2003
438 Genre: Soundtrack
439 Soundtrack
440 00:04:19 Layer III, 160 kbps, 44100 Hz, joint stereo (MS), no CRC
441
442# <i>ogg123 Paul\ Oakenfold\ -\ Dread\ Rock.ogg</i>
443Audio Device: Advanced Linux Sound Architecture (ALSA) output
444
445Playing: Paul Oakenfold - Dread Rock.ogg
446Ogg Vorbis stream: 2 channel, 44100 Hz
447Genre: Soundtrack
448Transcoded: mp3;160
449Title: Dread Rock
450Artist: Paul Oakenfold
451Date: 2003
452Album: Matrix Reloaded
453Time: 00:11.31 [04:28.75] of 04:40.06 (200.6 kbps) Output Buffer 96.9%
454</pre>
455
456</body>
457</section>
458<section>
459<title>ALSA and USE</title>
460<body>
461
462<p>
463You can now add the <c>alsa</c> use flag to <path>/etc/make.conf</path> to
464ensure that your applications that support ALSA get built with it. Some
465architectures like x86 and amd64 have the flag enabled by default.
466</p>
467
468</body>
469</section>
470<section>
471<title>Issues?</title>
472<body>
473
474<p>
475If for some reason you're unable to hear sound, the first thing to do would
476be to check your <uri link="#doc_chap3_pre6">alsamixer</uri> settings. 80% of
477the issues lie with muted channels or low volume. Also check your Window
478Manager's sound applet and verify that volumes are set to audible levels.
479</p>
480
481<p>
482<path>/proc</path> is your friend. And in this case, <path>/proc/asound</path>
483is your best friend. We shall just take a short look at how much info is made
484available to us there.
485</p>
486
487<pre caption="Fun with /proc/asound">
488<comment>(First and foremost, if /proc/asound/cards shows your card, ALSA has
489picked up your sound card fine.)</comment>
490# <i>cat /proc/asound/cards</i>
4910 [Live ]: EMU10K1 - Sound Blaster Live!
492 Sound Blaster Live! (rev.6, serial:0x80271102) at 0xb800, irq 11
493
494<comment>(This displays the current running ALSA version)</comment>
495# <i>cat /proc/asound/version</i>
496Advanced Linux Sound Architecture Driver Version 1.0.8 (Thu Jan 13 09:39:32 2005 UTC).
497
498<comment>(ALSA OSS emulation details)</comment>
499# <i>cat /proc/asound/oss/sndstat</i>
500Sound Driver:3.8.1a-980706 (ALSA v1.0.8 emulation code)
501Kernel: Linux airwolf.zion 2.6.11ac1 #2 Wed May 4 00:35:08 IST 2005 i686
502Config options: 0
503
504Installed drivers:
505Type 10: ALSA emulation
506
507Card config:
508Sound Blaster Live! (rev.6, serial:0x80271102) at 0xb800, irq 11
509
510Audio devices:
5110: EMU10K1 (DUPLEX)
512
513Synth devices: NOT ENABLED IN CONFIG
514
515Midi devices:
5160: EMU10K1 MPU-401 (UART)
517
518Timers:
5197: system timer
520
521Mixers:
5220: SigmaTel STAC9721/23
523</pre>
524
525<!-- TODO: remove this a few months after alsa-driver leaves the tree -->
526
527<p>
528The other most common issue users face is the dreaded "Unknown symbol in module"
529error. An example of the same is shown below.
530</p>
531
532<pre caption="Unknown Symbol in module error">
533# <i>/etc/init.d/alsasound start</i>
534 * Loading ALSA modules ...
535 * Loading: snd-card-0 ... [ ok ]
536 * Loading: snd-pcm-oss ...
537WARNING: Error inserting snd_mixer_oss
538(/lib/modules/2.6.12-gentoo-r6/kernel/sound/core/oss/snd-mixer-oss.ko): Unknown
539symbol in module, or unknown parameter (see dmesg) FATAL: Error inserting
540snd_pcm_oss
541(/lib/modules/2.6.12-gentoo-r6/kernel/sound/core/oss/snd-pcm-oss.ko): Unknown
542symbol in module, or unknown parameter (see dmesg)
543 [ !! ]
544 * Loading: snd-mixer-oss ...
545FATAL: Error inserting snd_mixer_oss
546(/lib/modules/2.6.12-gentoo-r6/kernel/sound/core/oss/snd-mixer-oss.ko): Unknown
547symbol in module, or unknown parameter (see dmesg)
548 [ !! ]
549 * Loading: snd-seq ... [ ok ]
550 * Loading: snd-emu10k1-synth ... [ ok ]
551 * Loading: snd-seq-midi ... [ ok ]
552 * Restoring Mixer Levels ... [ ok ]
553</pre>
554
555<p>
556And when you take a look at <c>dmesg</c> as suggested, you're quite likely to
557see:
558</p>
559
560<pre caption="dmesg output">
561<comment>(Only relevant portions are shown below)</comment>
562# <i>dmesg | less</i>
563ACPI: PCI Interrupt 0000:02:06.0[A] -> Link [APC3] -> GSI 18 (level, low) -> IRQ 209
564snd_mixer_oss: Unknown symbol snd_unregister_oss_device
565snd_mixer_oss: Unknown symbol snd_register_oss_device
566snd_mixer_oss: Unknown symbol snd_mixer_oss_notify_callback
567snd_mixer_oss: Unknown symbol snd_oss_info_register
568snd_pcm_oss: Unknown symbol snd_unregister_oss_device
569snd_pcm_oss: Unknown symbol snd_register_oss_device
570snd_pcm_oss: Unknown symbol snd_mixer_oss_ioctl_card
571snd_pcm_oss: Unknown symbol snd_oss_info_register
572snd_mixer_oss: Unknown symbol snd_unregister_oss_device
573snd_mixer_oss: Unknown symbol snd_register_oss_device
574snd_mixer_oss: Unknown symbol snd_mixer_oss_notify_callback
575snd_mixer_oss: Unknown symbol snd_oss_info_register
576</pre>
577
578<p>
579The above issue is caused when you switch from the <c>alsa-driver</c> to in-kernel
580ALSA because when you unmerge <c>alsa-driver</c> the module files are config
581protected and hence get left behind. So, when you switch to in-kernel
582drivers, running <c>modprobe</c> gives you a mix of <c>alsa-driver</c> and
583in-kernel modules thus causing the above errors.
584</p>
585
586<p>
587The solution is quite easy. We just need to manually remove the problem causing
588directory after you unmerge <c>alsa-driver</c>. Be sure to remove the correct
589kernel version and not the current one!
590</p>
591
592<pre caption="Removing the alsa-driver modules">
593# <i>rm -rf /lib/modules/$(uname -r)/alsa-driver</i>
594</pre>
595
596<p>
597Another reason for error messages similar to the ones above could be a file in
598<path>/etc/modprobe.d</path> supplying a <c>device_mode</c> parameter when it
599isn't required. Confirm that this is indeed the issue and find out which file
600is the culprit.
601</p>
602
603<pre caption="Confirming and searching for device_mode">
604<comment>(Check dmesg to confirm)</comment>
605# <i>dmesg | grep device_mode</i>
606snd: Unknown parameter `device_mode'
607<comment>(Now, to get to the source of the issue)</comment>
608# <i>grep device_mode /etc/modprobe.d/*</i>
609</pre>
610
611<p>
612Usually it is a file called <path>alsa</path> with the line <c>options snd
613device_mode=0666</c>. Remove this line and restart the <c>alsasound</c> service
614and that should take care of this issue.
615</p>
616
617<!-- End of removal notice -->
618
619</body>
620</section>
621</chapter>
622
623<chapter>
624<title>Other things ALSA</title>
625<section id="midi">
626<title>Setting up MIDI support</title>
627<body>
628
629<p>
630First, check to make sure that you enabled the <c>midi</c> USE flag in
631<path>/etc/make.conf</path>. If you didn't, go ahead and add it now. You will
632also need to re-emerge any ALSA packages that use the <c>midi</c> flag, such as
633<c>alsa-lib</c> and <c>alsa-utils</c>.
634</p>
635
636<p>
637If your sound card is one of those that come with on-board MIDI synthesizers
638and you would like to listen to some .mid files, you have to install
639<c>awesfx</c> which is basically a set of utilities for controlling the AWE32
640driver. We need to install it first. If you don't have a hardware synthesizer,
641you can use a virtual one. Please see the section on
642<uri link="#vsynth">Virtual Synthesizers</uri> for more information.
643</p>
644
645<pre caption="Installing awesfx">
646# <i>emerge awesfx</i>
647</pre>
648
202<note> 649<note>
203When you want to install ALSA drivers for more than one soundcard, you could set ALSA_CARDS to a space-separated list 650You will need to copy over SoundFont (SF2) files from your sound card's driver
204of drivers; like this: <c>env ALSA_CARDS='emu10k1 intel8x0 ens1370' emerge alsa-driver</c> 651CD or a Windows installation into <path>/usr/share/sounds/sf2/</path>. For
652example a sound font file for the Creative SBLive! card would be 8MBGMSFX.SF2.
205</note> 653</note>
206 654
207<note>If you want to have OSS compatibility, make sure to emerge <i>alsa-oss</i>, it is the ALSA/OSS compatibility
208wrapper. </note>
209
210<note>If you plan on recompiling your kernels numerous times, it might
211be adviseable to emerge <c>alsa-driver</c> with <c>--buildpkg</c>. This
212will create a binary package for it. Later, after recompiling your kernel,
213you can just do <c>emerge --usepkg alsa-driver</c> which will install the
214binary package instead of recompiling it completely.</note>
215
216<p>
217After this, the ALSA modules should be installed on your system.
218</p> 655<p>
219</body> 656After copying over the Soundfont files, we can then play a midi file as shown.
220</section> 657You can also add the <c>asfxload</c> command to
221<section> 658<path>/etc/conf.d/local.start</path>, so that the sound font is loaded
222 <title>Configuration of ALSA</title> 659every time the system starts up.
223<body>
224<p> 660</p>
225Let's start configuring now to get ALSA working properly.
226We'll need to edit some files, to let our system know about the freshly installed ALSA modules.
227</p>
228 661
229<p>
230First, install <c>alsa-utils</c> on your system:
231</p>
232
233<pre caption = "Emerging alsa-utils">
234# <i>emerge alsa-utils</i>
235</pre>
236
237<p>
238Hereafter, we need to edit <path>/etc/modules.d/alsa</path>.
239</p>
240<warn>
241There is no need to edit <path>/etc/modules.conf</path>. Instead, always edit files in <path>/etc/modules.d</path>.
242</warn>
243<p>
244Check the ALSA portion <e>at the bottom of the file</e>.
245By tweaking this line you can specify the max number of soundcards you have (generally, just one).
246</p>
247<pre caption="At the bottom of /etc/modules.d/alsa">
248<comment>Set this to the correct number of cards.</comment>
249options snd cards_limit=1
250</pre>
251<p>
252Now we'll specify the sounddriver(s) ALSA should use. In the same file, edit like this:
253</p>
254<pre caption="In /etc/modules.d/alsa">
255## and then run `modules-update' command.
256## Read alsa-driver's INSTALL file in /usr/share/doc for more info.
257##
258## ALSA portion
259alias snd-card-0 snd-emu10k1
260<comment>## If you have more than one, add:</comment>
261## alias snd-card-1 snd-intel8x0
262## alias snd-card-2 snd-ens1370
263## OSS/Free portion
264## alias sound-slot-0 snd-card-0
265## alias sound-slot-1 snd-card-1
266##
267</pre>
268<note> 662<note>
269If you have more than one soundcard, adjust the <c>cards_limit</c> value and add more snd-card aliases to the file. 663<path>/mnt</path> paths mentioned in the code listing(s) below will <e>not</e>
270I don't have experience with this, but you can find examples for configurations with two or more soundcards in 664be the same in your machine. They are just an example. Please be careful to
271<uri link="http://www.alsa-project.org/alsa-doc/alsa-howto/c1660.htm">Chapter 6</uri> 665change the path to suit your machine.
272of the <uri link="http://www.alsa-project.org/alsa-doc/alsa-howto/alsa-howto.html">ALSA Howto</uri>.
273</note> 666</note>
274<p> 667
275Last thing to do in this file, almost at the end, check if these lines are there and uncommented: 668<pre caption="Loading Soundfonts">
276</p> 669<comment>(First, copy the Soundfont)</comment>
277<pre caption="Near the end of /etc/modules.d/alsa"> 670# <i>cp /mnt/win2k/Program\ Files/CreativeSBLive2k/SFBank/8MBGMSFX.SF2 /usr/share/sounds/sf2/</i>
278alias /dev/mixer snd-mixer-oss 671<comment>(Or get it from your SoundBlaster CD)</comment>
279alias /dev/dsp snd-pcm-oss 672# <i>cp /mnt/cdrom/AUDIO/ENGLISH/SFBANK/8MBGMSFX.SF2 /usr/share/sounds/sf2/</i>
280alias /dev/midi snd-seq-oss 673<comment>(We load the specific Soundfont)</comment>
281</pre> 674# <i>asfxload /usr/share/sounds/sf2/8MBGMSFX.SF2</i>
282<p>
283Now double-check the file <path>/etc/modules.d/alsa</path> and when you're sure everyting is ok, run <c>modules-update</c>.
284<pre> 675</pre>
285# <i>modules-update</i> 676
286</pre>
287</p> 677<p>
288<note> 678You can now play midi files using a program like <c>aplaymidi</c>. Run
289Running <c>modules-update</c> here will insert the data from <path>/etc/modules.d/alsa</path> into <path>/etc/modules.conf</path> 679<c>aplaymidi -l</c> to get a list of available ports and then pick one
290</note> 680to play the file on.
291<p> 681</p>
292You should also verify that /etc/devfsd.conf has the alsa devices and permissions correctly registered. 682
683<pre caption="Playing MIDI">
684<comment>(Check open ports)</comment>
685# <i>aplaymidi -l</i>
686 Port Client name Port name
687 64:0 EMU10K1 MPU-401 (UART) EMU10K1 MPU-401 (UART)
688 65:0 Emu10k1 WaveTable Emu10k1 Port 0
689 65:1 Emu10k1 WaveTable Emu10k1 Port 1
690 65:2 Emu10k1 WaveTable Emu10k1 Port 2
691 65:3 Emu10k1 WaveTable Emu10k1 Port 3
692<comment>(Pick a port, and play a mid file)</comment>
693# <i> aplaymidi --port=65:0 /mnt/shyam/music/midi/mi2.mid</i>
293</p> 694</pre>
294<pre caption="/etc/devfsd.conf"> 695
295# ALSA/OSS stuff
296# Comment/change these if you want to change the permissions on
297# the audio devices
298LOOKUP snd MODLOAD ACTION snd
299LOOKUP dsp MODLOAD
300LOOKUP mixer MODLOAD
301LOOKUP midi MODLOAD
302REGISTER sound/.* PERMISSIONS root.audio 660
303REGISTER snd/.* PERMISSIONS root.audio 660
304</pre>
305<note>
306Notice that devfsd.conf sets /dev/sound permissions to be root.audio. Thus, for non-root users to use audio they will have to be part of the audio group.
307</note>
308</body> 696</body>
309</section>
310</chapter>
311<chapter>
312<title>Starting ALSA</title>
313<section> 697</section>
314 <title>Adding alsasound to a runlevel</title> 698<section id="vsynth">
315<body> 699<title>Virtual Synthesizers</title>
316<p>
317First thing to do now, is to make ALSA startup at boottime. Like this:
318<pre>
319# <i>rc-update add alsasound boot</i>
320</pre>
321</p>
322<p>
323<warn>Note that the alsasound script should be added to the "boot" runlevel, not the "default" runlevel.</warn>
324</p>
325</body> 700<body>
326</section> 701
702<p>
703If your sound card lacks a hardware synthesizer, you could use a virtual one
704like <c>timidity++</c>. Installation is a breeze.
705</p>
706
707<pre caption="Installing timidity++">
708# <i>emerge timidity++</i>
709</pre>
710
711<p>
712For timidity to play sounds, it needs a sound font. Fortunately, the ebuild will
713install some sound font packages for you. There are a few other font packages
714available in Portage, such as <c>timidity-freepats</c> and
715<c>timidity-eawpatches</c>. You can have multiple sound font configurations
716installed, and you can place your own in <path>/usr/share/timidity/</path>. To
717switch between different timidity configurations, you should use
718<c>eselect</c>.
719</p>
720
721<pre caption="Changing configurations">
722# <i>eselect timidity list</i>
723# <i>eselect timidity set eawpatches</i>
724</pre>
725
726<p>
727Don't forget to add <c>timidity</c> to the default runlevel.
728</p>
729
730<pre caption="Adding timidity to the default runlevel">
731# <i>rc-update add timidity default</i>
732# <i>/etc/init.d/timidity start</i>
733</pre>
734
735<p>
736You can now try out <uri link="#doc_chap4_pre3">Playing MIDI</uri> files.
737</p>
738
739</body>
327<section> 740</section>
328 <title>Running and unmuting</title>
329<body>
330<p>
331Since we're Linux users, we don't want to reboot. So we'll start the alsasound script manually.
332</p>
333<pre>
334# <i>/etc/init.d/alsasound start</i>
335</pre>
336<p>
337ALSA is running now. If everything is ok, you should be able to see the ALSA modules loaded when running <c>lsmod</c>.
338However, sound won't work yet, because the channels are still muted. We need <c>amixer</c> for this.
339</p>
340<pre caption = "Running amixer">
341# <i>amixer</i>
342</pre>
343<p>
344<warn>
345You shouldn't get this, but <e>if</e> you get an error about "amixer: Mixer attach default error: No such file or directory", you should manually modprobe
346<c>snd-mixer-oss</c> and <c>snd-pcm-oss</c> once. After that run amixer again.
347</warn>
348</p>
349<pre caption="only if you get an error when running amixer">
350# <i>modprobe snd-mixer-oss</i>
351# <i>modprobe snd-pcm-oss</i>
352# <i>amixer</i>
353</pre>
354<p>
355If you got this far, now unmute Master and PCM channels. Some hardware
356even requires you to unmute the center channel or even the surround
357channel.
358</p>
359<p>
360<pre caption = "Unmuting channels">
361# <i>amixer set Master 100 unmute</i>
362# <i>amixer set PCM 100 unmute</i>
363<comment>Only if the above doesn't succeed on its own:</comment>
364# <i>amixer set Center 100 unmute</i>
365# <i>amixer set Surround 100 unmute</i>
366<comment>Test the sound:</comment>
367# <i>aplay $KDEDIR/share/sounds/pop.wav</i> <codenote>(pop.wav is part of KDE)</codenote>
368</pre>
369</p>
370We check to see if sound is working by using the aplay (alsa play) command. If you hear a pop, then sound is indeed working.
371Then, adjust the volume settings to your liking; the ncurses-based <c>alsamixer</c> is a great way to get them "just so".
372<p>
373You may want to emerge <c>alsa-xmms</c> as that will provide ALSA support for XMMS.
374</p>
375When you reboot your system, the <e>alsasound</e> init script will properly save and restore your volume settings.
376</body>
377</section> 741<section>
378</chapter> 742<title>Tools and Firmware</title>
379<chapter> 743<body>
380<title>Final Notes</title> 744
745<p>
746Some specific sound cards can benefit from certain tools provided by the
747<c>alsa-tools</c> and <c>alsa-firmware</c> packages. You may install either with
748a simple <c>emerge</c>.
749</p>
750
751<pre caption="Installing ALSA Tools">
752# <i>emerge alsa-tools</i>
753</pre>
754
755</body>
381<section> 756</section>
382 <title>After kernel-upgrades..</title>
383<body>
384<p>When you ever rebuild your kernel, or upgrade to another kernel, you'll have to rebuild the ALSA modules.</p>
385<p>Although you might have installed <c>alsa-driver</c>, <c>alsa-libs</c> and <c>alsa-utils</c>, only the first will
386have to be installed again, since it will put the alsa modules in
387<path>/lib/modules/*/kernel/sound/pci/</path>.</p>
388<pre caption="needed after each kernel compile">
389# <i>emerge alsa-driver</i>
390</pre>
391</body>
392</section> 757<section>
758<title>Multiple sound cards</title>
759<body>
760
761<p>
762You can have more than one sound card in your system simultaneously, provided
763that you have built ALSA as modules in your kernel. You just need to specify
764which should be started first in <path>/etc/modprobe.d/alsa.conf</path>. Your cards
765are identified by their driver names inside this file. 0 is the first card, 1 is
766the second, and so on. Here's an example for a system with two sound cards.
767</p>
768
769<pre caption="Two sound cards in /etc/modprobe.d/alsa.conf">
770options snd-emu10k1 index=0
771options snd-via82xx index=1
772</pre>
773
774<p>
775Or, if you have two cards that use the same driver, you specify them on the same
776line, using comma-separated numbers. Here's an example for a system with three
777sound cards, two of which are the same Intel High Definition Audio card.
778</p>
779
780<pre caption="Multiple sound cards in /etc/modprobe.d/alsa.conf">
781options snd-ymfpci index=0
782options snd-hda-intel index=1,2
783</pre>
784
785</body>
393<section> 786</section>
394 <title>/etc/modules.autoload</title>
395<body>
396<p>You won't have to edit this file for use with ALSA. After our <c>rc-update add alsasound boot</c>, our system will
397load the correct modules at startup.</p>
398<p>It's not necessary to add <c>snd-pcm-oss</c> or <c>snd-mixer-oss</c> in this file.
399Check the <uri link="http://www.djcj.org/LAU/guide/alsbook/faq1.html">this FAQ</uri> for more info.</p>
400</body>
401</section> 787<section>
788<title>Plugins</title>
789<body>
402 790
791<p>
792You may want to install some plugins for extra functionality.
793<c>alsa-plugins</c> is a collection of useful plugins, which include: PulseAudio
794output, a sample rate converter, jack (a low-latency audio server), and an
795encoder that lets you output 6-channel audio through digital S/PDIF connections
796(both optical and coaxial). You can choose which of its plugins you want
797installed by adding their USE flags to <path>/etc/portage/package.use</path>.
798</p>
799
800<pre caption="Installing alsa-plugins">
801# <i>emerge -avt alsa-plugins</i>
802</pre>
803
804</body>
403<section> 805</section>
404<title>Known bugs</title> 806<section>
807<title>A big thank you to...</title>
808<body>
809
810<p>
811Everyone who contributed to the earlier version of the Gentoo ALSA Guide:
812Vincent Verleye, Grant Goodyear, Arcady Genkin, Jeremy Huddleston,
813John P. Davis, Sven Vermeulen, Benny Chuang, Tiemo Kieft and Erwin.
814</p>
815
405<body> 816</body>
406 817</section>
407<note> 818<section>
408This guide lags behind on the alsa-development. Chances are these bugs 819<title>References</title>
409are already fixed when you read this. 820<body>
410</note>
411 821
412<ul> 822<ul>
413<li> 823 <li><uri link="http://www.alsa-project.org/">The ALSA Project</uri></li>
414If you have <b>lots of noise</b> when using <b>oss</b> emulation, add 824 <li><uri link="http://linux-sound.org">Linux Sound/MIDI Software</uri></li>
415<e>options snd-pcm-oss dsp_map=1</e> to
416<path>/etc/modules.d/alsa</path>.
417</li>
418</ul> 825</ul>
419 826
420</body>
421</section>
422
423<section>
424 <title>More links..</title>
425<body>
426<p>
427You could check these for additional info:
428</p>
429<p>
430<ul>
431<li><uri link="http://www.gentoo.org/doc/en/desktop.xml">The Gentoo Linux Desktop Configuration Guide</uri></li>
432<li><uri link="http://www.alsa-project.org">ALSA Project Homepage</uri></li>
433<li><uri link="http://www.alsa-project.org/documentation.php3">ALSA Users Documentation</uri></li>
434<li><uri link="http://www.djcj.org">ALSA Howto's and FAQ's</uri></li>
435<li><uri link="http://tldp.org/HOWTO/Sound-HOWTO/index.html">Linux Sound HOWTO</uri></li>
436<li><uri link="http://linux-sound.org/">Sound and MIDI Software For Linux</uri></li>
437</ul>
438</p>
439</body> 827</body>
440</section> 828</section>
441</chapter> 829</chapter>
442</guide> 830</guide>

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