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1 <?xml version='1.0' encoding="UTF-8"?>
2 <!-- $Header: /var/cvsroot/gentoo/xml/htdocs/doc/en/alsa-guide.xml,v 1.72 2007/01/31 16:39:26 nightmorph Exp $ -->
3
4 <!DOCTYPE guide SYSTEM "/dtd/guide.dtd">
5
6 <guide link="/doc/en/alsa-guide.xml">
7 <title>Gentoo Linux ALSA Guide</title>
8
9 <author title="Author">
10 <mail link="fox2mike@gentoo.org">Shyam Mani</mail>
11 </author>
12 <author title="Author">
13 <mail link="nightmorph@gentoo.org">Joshua Saddler</mail>
14 </author>
15 <author title="Contributor">
16 <mail link="flameeyes@gentoo.org">Diego Pettenò</mail>
17 </author>
18
19 <abstract>
20 This 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 -->
25 <license/>
26
27 <version>2.17</version>
28 <date>2007-02-17</date>
29
30 <chapter>
31 <title>Introduction</title>
32 <section>
33 <title>What is ALSA?</title>
34 <body>
35
36 <p>
37 ALSA, which stands for <e>Advanced Linux Sound Architecture</e>, provides
38 audio and MIDI (<e>Musical Instrument Digital Interface</e>) functionality to
39 the Linux operating system. ALSA is the default sound subsystem in the 2.6
40 kernel thereby replacing OSS (<e>Open Sound System</e>), which was used in the
41 2.4 kernels.
42 </p>
43
44 <p>
45 ALSA's main features include efficient support for all types of audio
46 interfaces ranging from consumer sound cards to professional sound
47 equipment, fully modularized drivers, SMP and thread safety, backward
48 compatibility with OSS and a user-space library <c>alsa-lib</c> to make
49 application development a breeze.
50 </p>
51
52 </body>
53 </section>
54 <section>
55 <title>ALSA on Gentoo</title>
56 <body>
57
58 <p>
59 One of Gentoo's main strengths lies in giving the user maximum control over
60 how a system is installed/configured. ALSA on Gentoo follows the same
61 principle. There are two ways you can get ALSA support up and running on your
62 system. We shall look at them in detail in the next chapter.
63 </p>
64
65 </body>
66 </section>
67 </chapter>
68
69 <chapter>
70 <title>Installing ALSA</title>
71 <section>
72 <title>Options</title>
73 <body>
74
75 <warn>
76 The methods shown below are mutually exclusive. You cannot have ALSA compiled
77 in your kernel and use <c>media-sound/alsa-driver</c>. It <e>will</e> fail.
78 </warn>
79
80 <p>
81 The two options are :
82 </p>
83
84 <ol>
85 <li>Use ALSA provided by your kernel.</li>
86 <li>Use Gentoo's <c>media-sound/alsa-driver</c> package.</li>
87 </ol>
88
89 <p>
90 The in-kernel drivers and the <c>alsa-driver</c> package can vary a little; it's
91 possible that features and fixes found in one might not yet be incorporated into
92 the other. The upstream developers are aware of this, but the two drivers are
93 effectively separate branches of the ALSA project; they are not entirely
94 identical. You should be aware that they might function slightly differently, so
95 if one doesn't work for you, try the other! We shall take a peek into both
96 before finally deciding on one.
97 </p>
98
99 <p>
100 If you were to use ALSA provided by the kernel, the following are the pros and
101 cons :
102 </p>
103
104 <table>
105 <tr>
106 <th>Kernel ALSA</th>
107 <th>Pros and Cons</th>
108 </tr>
109 <tr>
110 <th>+</th>
111 <ti>
112 No need to emerge yet another package; drivers are integrated into kernel.
113 </ti>
114 </tr>
115 <tr>
116 <th>+</th>
117 <ti>One shot solution, no repeating emerges.</ti>
118 </tr>
119 <tr>
120 <th>-</th>
121 <ti>Might be a slightly different version than <c>alsa-driver</c>.</ti>
122 </tr>
123 </table>
124
125 <p>
126 And, if you were to use alsa-driver,
127 </p>
128
129 <table>
130 <tr>
131 <th>alsa-driver</th>
132 <th>Pros and Cons</th>
133 </tr>
134 <tr>
135 <th>+</th>
136 <ti>Possibly the latest drivers from the ALSA Project.</ti>
137 </tr>
138 <tr>
139 <th>+</th>
140 <ti>Useful if you intend to develop audio drivers.</ti>
141 </tr>
142 <tr>
143 <th>-</th>
144 <ti>Every kernel recompile requires a re-emerge of <c>alsa-driver</c>.</ti>
145 </tr>
146 <tr>
147 <th>-</th>
148 <ti>Needs certain kernel config options disabled to work correctly.</ti>
149 </tr>
150 </table>
151
152 </body>
153 </section>
154 <section>
155 <title>So...</title>
156 <body>
157
158 <p>
159 The differences between <c>alsa-driver</c> and the in-kernel ALSA drivers are
160 quite subtle, as mentioned earlier. Since there are not any huge differences,
161 this guide will go through the process of using the ALSA provided by the kernel
162 <e>first</e> for ease of use. However, if you run into problems, try switching
163 to <c>alsa-driver</c>. Before reporting any sound related issues to <uri
164 link="https://bugs.gentoo.org">Gentoo Bugzilla</uri>, please try to reproduce
165 them using <c>alsa-driver</c> and file the bug report no matter what the
166 result.
167 </p>
168
169 </body>
170 </section>
171 <section id="lspci">
172 <title>Before you proceed</title>
173 <body>
174
175 <p>
176 Whichever method of install you choose, you need to know what drivers your
177 sound card uses. In most cases, sound cards (onboard and otherwise) are PCI
178 based and <c>lspci</c> will help you in digging out the required information.
179 Please <c>emerge sys-apps/pciutils</c> to get <c>lspci</c>, if you don't have it
180 installed already. In case you have a USB sound card, <c>lsusb</c> from
181 <c>sys-apps/usbutils</c> <e>might</e> be of help. For ISA cards, try using
182 <c>sys-apps/isapnptools</c>. Also, the following pages <e>may</e> help users
183 with ISA based sound cards.
184 </p>
185
186 <ul>
187 <li>
188 <uri link="http://www.roestock.demon.co.uk/isapnptools/">The ISAPNPTOOLS
189 Page</uri>
190 </li>
191 <li>
192 <uri link="http://www2.linuxjournal.com/article/3269">LinuxJournal PnP
193 Article</uri>
194 </li>
195 <li>
196 <uri link="http://www.tldp.org/HOWTO/Sound-HOWTO/x320.html">TLDP Sound
197 HowTo</uri>
198 </li>
199 </ul>
200
201 <note>
202 For ease of use/explanation, we assume the user has a PCI based sound card for
203 the remainder of this guide.
204 </note>
205
206 <p>
207 We now proceed to find out details about the sound card.
208 </p>
209
210 <pre caption="Soundcard Details">
211 # <i>lspci -v | grep -i audio</i>
212 0000:00:0a.0 Multimedia audio controller: Creative Labs SB Live! EMU10k1 (rev 06)
213 </pre>
214
215 <p>
216 We now know that the sound card on the machine is a Sound Blaster Live! and
217 the card manufacturer is Creative Labs. Head over to the
218 <uri link="http://www.alsa-project.org/alsa-doc/"> ALSA Soundcard Matrix</uri>
219 page and select Creative Labs from the drop down menu. You will be taken to
220 the Creative Labs matrix page where you can see that the SB Live! uses the
221 <c>emu10k1</c> module. That is the information we need for now. If you are
222 interested in detailed information, you can click on the link next to the
223 "Details" and that will take you to the <c>emu10k1</c> specific page.
224 </p>
225
226 <p>
227 If you intend to use MIDI, then you should add <c>midi</c> to your USE flags in
228 <path>/etc/make.conf</path> before emerging any ALSA packages. Later in the
229 guide, we will show you how to set up <uri link="#midi">MIDI support</uri>.
230 </p>
231
232 <pre caption="MIDI support in /etc/make.conf">
233 <comment>(If you want MIDI support)</comment>
234 USE="midi"
235
236 <comment>(If you don't need MIDI)</comment>
237 USE="-midi"
238 </pre>
239
240 </body>
241 </section>
242 <section id="kernel">
243 <title>Using ALSA provided by your Kernel</title>
244 <body>
245
246 <p>
247 If you're a person who likes to keep things simple like I do, then this is
248 the way to go.
249 </p>
250
251 <note>
252 Since the 2005.0 release, Gentoo Linux uses 2.6 as the default kernel. Unless
253 you are specifically using the 2.4 profile, <c>gentoo-sources</c> will be a
254 2.6 kernel on <e>most</e> architectures. Please check that your kernel is a
255 2.6 series kernel. This method will <e>not</e> work on a 2.4 kernel.
256 </note>
257
258 <p>
259 Let us now configure the kernel to enable ALSA.
260 </p>
261
262 <impo>
263 <c>genkernel</c> users should now run <c>genkernel --menuconfig all</c> and
264 then follow the instructions in <uri link="#doc_chap2_pre3">Kernel Options for
265 ALSA</uri>.
266 </impo>
267
268 <pre caption="Heading over to the source">
269 # <i>cd /usr/src/linux</i>
270 # <i>make menuconfig</i>
271 </pre>
272
273 <note>
274 The above example assumes that <path>/usr/src/linux</path> symlink points to
275 the kernel sources you want to use. Please ensure the same before proceeding.
276 </note>
277
278 <p>
279 Now we will look at some of the options we will have to enable in the 2.6
280 kernel to ensure proper ALSA support for our sound card.
281 </p>
282
283 <p>
284 Please note that for ease of use, all examples show ALSA built as modules. It
285 is advisable to follow the same as it then allows the use of <c>alsaconf</c>
286 which is a boon when you want to configure your card. Please do <e>not</e> skip
287 the <uri link="#alsa-config">Configuration</uri> section of this document. If
288 you still like to have options built-in, ensure that you make changes to your
289 config accordingly.
290 </p>
291
292 <pre caption="Kernel Options for ALSA">
293 Device Drivers ---&gt;
294 Sound ---&gt;
295
296 <comment>(This needs to be enabled)</comment>
297 &lt;M&gt; Sound card support
298
299 <comment>(Make sure OSS is disabled)</comment>
300 Open Sound System ---&gt;
301 &lt; &gt; Open Sound System (DEPRECATED)
302
303 <comment>(Move one step back and enter ALSA)</comment>
304 Advanced Linux Sound Architecture ---&gt;
305 &lt;M&gt; Advanced Linux Sound Architecture
306 <comment>(Select this if you want MIDI sequencing and routing)</comment>
307 &lt;M&gt; Sequencer support
308 <comment>(Old style /dev/mixer* and /dev/dsp* support. Recommended.)</comment>
309 &lt;M&gt; OSS Mixer API
310 &lt;M&gt; OSS PCM (digital audio) API
311
312 <comment>(You now have a choice of devices to enable support for. Generally,
313 you will have one type of device and not more. If you have more than one
314 sound card, please enable them all here.)</comment>
315
316 <comment>(Mostly for testing and development purposes, not needed for normal
317 users unless you know what you are doing.)</comment>
318 Generic devices ---&gt;
319
320 <comment>(For ISA Sound cards)</comment>
321 ISA devices ---&gt;
322 <comment>(IF you had the Gravis, you would select this option)</comment>
323 &lt;M&gt; Gravis UltraSound Extreme
324
325 <comment>(Move one level back and into PCI devices. Most sound cards today are
326 PCI devices)</comment>
327 PCI devices ---&gt;
328 <comment>(We now select the emu10k1 driver for our card)</comment>
329 &lt;M&gt; Emu10k1 (SB Live!, Audigy, E-mu APS)
330 <comment>(Or an Intel card would be)</comment>
331 &lt;M&gt; Intel/SiS/nVidia/AMD/ALi AC97 Controller
332 <comment>(Or if you have a VIA Card)</comment>
333 &lt;M&gt; VIA 82C686A/B, 8233/8235 AC97 Controller
334
335 <comment>(Move one level back and select in case you have an USB sound card)</comment>
336 USB Devices ---&gt;
337 </pre>
338
339 <p>
340 Now that your options are set, you can (re)compile the kernel and ALSA support
341 for your card should be functional once you reboot into the new kernel. Don't
342 forget to update your GRUB configuration to use the newly built kernel.
343 You can now proceed to <uri link="#alsa-utilities">ALSA Utilities</uri> and
344 see if everything is working as it should.
345 </p>
346
347 </body>
348 </section>
349 <section id="alsa-driver">
350 <title>Using the ALSA Driver package</title>
351 <body>
352
353 <p>
354 So you've decided to go the <c>alsa-driver</c> way. Let's get started then.
355 There are a few minor things to be done to ensure only the drivers for your
356 sound card are compiled. Although this is not really necessary, it cuts down
357 on the unnecessary drivers that will be compiled otherwise.
358 </p>
359
360 <p>
361 If you don't have an idea of what drivers your sound card might need, please
362 take a look at the <uri link="#lspci">lspci</uri> section of this guide. Once
363 you have your driver name (<c>emu10k1</c> in our example), edit
364 <path>/etc/make.conf</path> and add a variable, <c>ALSA_CARDS</c>.
365 </p>
366
367 <pre caption="Adding ALSA_CARDS to make.conf">
368 <comment>(For one sound card)</comment>
369 ALSA_CARDS="emu10k1"
370 <comment>(For more than one, separate names with spaces)</comment>
371 ALSA_CARDS="emu10k1 via82xx"
372 </pre>
373
374 <p>
375 If you have compiled your kernel and want to use <c>alsa-driver</c>, please
376 ensure the following before proceeding, else <c>alsa-driver</c> is likely to
377 fail. The next code listing gives you one way of performing the checks.
378 </p>
379
380 <note>
381 <c>genkernel</c> users can proceed with <uri link="#doc_chap2_pre6">Installing
382 alsa-driver</uri> as their configuration is in sync with the one shown below by
383 default.
384 </note>
385
386 <ol>
387 <li>
388 <c>CONFIG_SOUND</c> is set. (Basic Sound support enabled)
389 </li>
390 <li>
391 <c>CONFIG_SOUND_PRIME</c> is not set. (In-built OSS support disabled)
392 </li>
393 <li>
394 <c>CONFIG_SND</c> is not set. (In-built ALSA support disabled)
395 </li>
396 <li>
397 <path>/usr/src/linux</path> points to the kernel you want ALSA working on.
398 </li>
399 </ol>
400
401 <pre caption=".config checks">
402 <comment>(Assuming the linux symlink points to the correct kernel)</comment>
403 # <i>cd /usr/src/linux</i>
404 # <i>grep SOUND .config</i>
405 <comment>(1. is true)</comment>
406 CONFIG_SOUND=y
407 <comment>(2. is true)</comment>
408 CONFIG_SOUND_PRIME is not set
409 # <i>grep SND .config</i>
410 <comment>(and 3. is true)</comment>
411 CONFIG_SND is not set
412 </pre>
413
414 <p>
415 Now all you have to do is type the magic words... and no, it's not abracadabra.
416 </p>
417
418 <pre caption="Installing alsa-driver">
419 # <i>emerge alsa-driver</i>
420 </pre>
421
422 <impo>
423 Please note that you will have to run <c>emerge alsa-driver</c> after every
424 kernel (re)compile, as the earlier drivers are deleted. To make this task
425 easier, you may want to emerge the <c>module-rebuild</c> package, which will
426 keep track of module packages and rebuild them for you. First run
427 <c>module-rebuild populate</c> to create the list, and then after every kernel
428 (re)compile, you just run <c>module-rebuild rebuild</c>, and your external
429 modules will be rebuilt.
430 </impo>
431
432 </body>
433 </section>
434 </chapter>
435
436 <chapter>
437 <title>Configuring/Testing ALSA</title>
438 <section id="alsa-utilities">
439 <title>ALSA Utilities</title>
440 <body>
441
442 <p>
443 <c>alsa-utils</c> forms an integral part of ALSA as it has a truckload of
444 programs that are highly useful, including the ALSA Initscripts. Hence we
445 strongly recommend that you install <c>alsa-utils</c>
446 </p>
447
448 <pre caption="Install alsa-utils">
449 # <i>emerge alsa-utils</i>
450 </pre>
451
452 <note>
453 If you activated ALSA in your <uri link="#kernel">kernel</uri> <e>and</e> did
454 not compile ALSA as modules, please proceed to the
455 <uri link="#initscript">ALSA Initscript</uri> section. The rest of you need
456 to configure ALSA. This is made very easy by the existence of the
457 <c>alsaconf</c> tool provided by <c>alsa-utils</c>.
458 </note>
459
460 </body>
461 </section>
462 <section id="alsa-config">
463 <title>Configuration</title>
464 <body>
465
466 <p>
467 Recent versions of <c>udev</c> (<c>>=udev-103</c>) provide some degree of
468 kernel-level autoconfiguration of your sound card. If possible, try to rely on
469 just letting your kernel automatically setup your sound card for you. Otherwise,
470 use <c>alsaconf</c> to configure your card, as shown below.
471 </p>
472
473 <note>
474 Please shut down any programs that <e>might</e> access the sound card while
475 running <c>alsaconf</c>.
476 </note>
477
478 <p>
479 Another way to configure your sound card is to run <c>alsaconf</c>. Just type
480 <c>alsaconf</c> in a shell as root.
481 </p>
482
483 <pre caption="Invoking alsaconf">
484 # <i>alsaconf</i>
485 </pre>
486
487 <p>
488 You will now see a neat menu guided interface that will automatically probe
489 your devices and try to find out your sound card. You will be asked to pick
490 your sound card from a list. Once that's done, it will ask you permission to
491 automatically make required changes to <path>/etc/modules.d/alsa</path>.
492 It will then adjust your volume settings to optimum levels, run
493 <c>modules-update</c> and start the <path>/etc/init.d/alsasound</path> service.
494 Once <c>alsaconf</c> exits, you can proceed with setting up the ALSA
495 initscript.
496 </p>
497
498 </body>
499 </section>
500 <section id="initscript">
501 <title>ALSA Initscript</title>
502 <body>
503
504 <p>
505 We're now almost all setup. Whichever method you chose to install ALSA, you'll
506 need to have something load your modules or initialize ALSA and restore your
507 volume settings when your system comes up. The ALSA Initscript handles all of
508 this for you and is called <c>alsasound</c>. Add it to the boot runlevel.
509 </p>
510
511 <pre caption="Adding ALSA to the boot runlevel">
512 # <i>rc-update add alsasound boot</i>
513 * alsasound added to runlevel boot
514 * rc-update complete.
515 </pre>
516
517 <p>
518 Next, just check the <path>/etc/conf.d/alsasound</path> file and ensure that
519 SAVE_ON_STOP variable is set to yes. This saves your sound settings when you
520 shutdown your system.
521 </p>
522
523 </body>
524 </section>
525 <section>
526 <title>Audio Group</title>
527 <body>
528
529 <p>
530 Before we move on to testing, there's one last <e>important</e> thing that needs
531 to be setup. Rule of thumb in a *nix OS : Do not run as root unless needed.
532 This applies here as well ;) How? Well, most of the times you should be logged
533 in as a user and would like to listen to music or access your soundcard. For
534 that to happen, you need to be in the "audio" group. At this point, we'll add
535 users to the audio group, so that they won't have any issues when they want to
536 access sound devices. We'll use <c>gpasswd</c> here and you need to be logged in
537 as root for this to work.
538 </p>
539
540 <pre caption="Adding users to the audio group">
541 <comment>(Substitute &lt;username&gt; with your user)</comment>
542 # <i>gpasswd -a &lt;username&gt; audio </i>
543 Adding user &lt;username&gt; to group audio
544 </pre>
545
546 </body>
547 </section>
548 <section>
549 <title>Volume Check!</title>
550 <body>
551
552 <p>
553 We've completed all the setups and prerequisites, so let's fire up ALSA. If
554 you ran <c>alsaconf</c>, you can skip this step, since <c>alsaconf</c> already
555 does this for you.
556 </p>
557
558 <pre caption="Start the service">
559 # <i>/etc/init.d/alsasound start</i>
560 </pre>
561
562 <p>
563 Now that the required things have been taken care of, we need to check up on
564 the volume as in certain cases, it is muted. We use <c>alsamixer</c> for this
565 purpose.
566 </p>
567
568 <pre caption="Starting alsamixer">
569 <comment>(Opens up a console program. Only required settings are shown)</comment>
570 # <i>alsamixer</i>
571 </pre>
572
573 <impo>
574 If you have issues starting up <c>alsamixer</c> and get errors such as
575 alsamixer: function snd_ctl_open failed for default: No such file or directory,
576 this is usually an issue with udev setting up the devices. Run <c>killall
577 udevd; udevstart</c> to reload <path>/dev</path> entries and fire up
578 <c>alsamixer</c>. It should solve the issue.
579 </impo>
580
581 <p>
582 This is how the ALSA Mixer <e>might</e> look the first time you open it. Pay
583 attention to the Master and PCM channels which both have an MM below them.
584 That means they are muted. If you try to play anything with <c>alsamixer</c>
585 in this state, you will not hear anything on your speakers.
586 </p>
587
588 <figure link="/images/docs/alsa-mixermuted.png" short="AlsaMixer Muted" caption="The Alsa Mixer Main Window, Muted"/>
589
590 <p>
591 Now, we shall unmute the channels, and set volume levels as needed.
592 </p>
593
594 <warn>
595 Both Master <e>and</e> PCM need to be unmuted and set to audible volume levels
596 if you want to hear some output on your speakers.
597 </warn>
598
599 <ul>
600 <li>
601 To move between channels, use your left and right arrow keys. (&lt;-
602 &amp; -&gt;)
603 </li>
604 <li>
605 To toggle mute, move to the specific channel, for example Master and press
606 the <e>m</e> key on the keyboard.
607 </li>
608 <li>
609 To increase and decrease the volume levels, use the up and down arrow keys
610 respectively.
611 </li>
612 </ul>
613
614 <note>
615 Be careful when setting your Bass and Treble values. 50 is usually a good
616 number for both. Extremely high values of Bass may cause <e>jarring</e>
617 on speakers that are not designed to handle them.
618 </note>
619
620 <p>
621 After you're all done, your ALSA Mixer should look similar to the one below.
622 Note the 00 instead of the MM and also the volume levels for some optimum
623 settings.
624 </p>
625
626 <figure link="/images/docs/alsa-mixerunmuted.png" short="AlsaMixer Unmuted" caption="Alsa Mixer ready to roll"/>
627
628 </body>
629 </section>
630 <section>
631 <title>Sound Check!</title>
632 <body>
633
634 <p>
635 Finally. Some music. If everything above is perfect, you should now be able to
636 listen to some good music. A quick way to test is to use a command line tool
637 like <c>media-sound/madplay</c>. You could also use something more well known
638 like <c>mpg123</c>. If you are an ogg fan, you could use <c>ogg123</c> provided
639 by <c>media-sound/vorbis-tools</c>. Use any player you are comfortable with. As
640 always, <c>emerge</c> what you need.
641 </p>
642
643 <pre caption="Getting the software">
644 <comment>(Install the applications you want)</comment>
645 # <i>emerge madplay mpg123</i>
646 <comment>(To play .ogg files)</comment>
647 # <i>emerge vorbis-tools</i>
648 </pre>
649
650 <p>
651 And then play your favorite sound track...
652 </p>
653
654 <pre caption="Playing Music">
655 # <i>madplay -v /mnt/shyam/Music/Paul\ Oakenfold\ -\ Dread\ Rock.mp3</i>
656 MPEG Audio Decoder 0.15.2 (beta) - Copyright (C) 2000-2004 Robert Leslie et al.
657 Title: Dread Rock
658 Artist: Paul Oakenfold
659 Album: Matrix Reloaded
660 Year: 2003
661 Genre: Soundtrack
662 Soundtrack
663 00:04:19 Layer III, 160 kbps, 44100 Hz, joint stereo (MS), no CRC
664
665 # <i>ogg123 Paul\ Oakenfold\ -\ Dread\ Rock.ogg</i>
666 Audio Device: Advanced Linux Sound Architecture (ALSA) output
667
668 Playing: Paul Oakenfold - Dread Rock.ogg
669 Ogg Vorbis stream: 2 channel, 44100 Hz
670 Genre: Soundtrack
671 Transcoded: mp3;160
672 Title: Dread Rock
673 Artist: Paul Oakenfold
674 Date: 2003
675 Album: Matrix Reloaded
676 Time: 00:11.31 [04:28.75] of 04:40.06 (200.6 kbps) Output Buffer 96.9%
677 </pre>
678
679 </body>
680 </section>
681 <section>
682 <title>ALSA and USE</title>
683 <body>
684
685 <p>
686 You can now add the <c>alsa</c> use flag to <path>/etc/make.conf</path> to
687 ensure that your applications that support ALSA get built with it. Some
688 architectures like x86 and amd64 have the flag enabled by default.
689 </p>
690
691 </body>
692 </section>
693 <section>
694 <title>Issues?</title>
695 <body>
696
697 <p>
698 If for some reason you're unable to hear sound, the first thing to do would
699 be to check your <uri link="#doc_chap3_pre6">alsamixer</uri> settings. 80% of
700 the issues lie with muted channels or low volume. Also check your Window
701 Manager's sound applet and verify that volumes are set to audible levels.
702 </p>
703
704 <p>
705 <path>/proc</path> is your friend. And in this case, <path>/proc/asound</path>
706 is your best friend. We shall just take a short look at how much info is made
707 available to us there.
708 </p>
709
710 <pre caption="Fun with /proc/asound">
711 <comment>(First and foremost, if /proc/asound/cards shows your card, ALSA has
712 picked up your sound card fine.)</comment>
713 # <i>cat /proc/asound/cards</i>
714 0 [Live ]: EMU10K1 - Sound Blaster Live!
715 Sound Blaster Live! (rev.6, serial:0x80271102) at 0xb800, irq 11
716
717 <comment>(If you run ALSA off the kernel like I do and wonder how far behind
718 you are from alsa-driver, this displays current running ALSA version)</comment>
719 # <i>cat /proc/asound/version</i>
720 Advanced Linux Sound Architecture Driver Version 1.0.8 (Thu Jan 13 09:39:32 2005 UTC).
721
722 <comment>(ALSA OSS emulation details)</comment>
723 # <i>cat /proc/asound/oss/sndstat</i>
724 Sound Driver:3.8.1a-980706 (ALSA v1.0.8 emulation code)
725 Kernel: Linux airwolf.zion 2.6.11ac1 #2 Wed May 4 00:35:08 IST 2005 i686
726 Config options: 0
727
728 Installed drivers:
729 Type 10: ALSA emulation
730
731 Card config:
732 Sound Blaster Live! (rev.6, serial:0x80271102) at 0xb800, irq 11
733
734 Audio devices:
735 0: EMU10K1 (DUPLEX)
736
737 Synth devices: NOT ENABLED IN CONFIG
738
739 Midi devices:
740 0: EMU10K1 MPU-401 (UART)
741
742 Timers:
743 7: system timer
744
745 Mixers:
746 0: SigmaTel STAC9721/23
747 </pre>
748
749 <p>
750 The other most common issue users face is the dreaded "Unknown symbol in module"
751 error. An example of the same is shown below.
752 </p>
753
754 <pre caption="Unknown Symbol in module error">
755 # <i>/etc/init.d/alsasound start</i>
756 * Loading ALSA modules ...
757 * Loading: snd-card-0 ... [ ok ]
758 * Loading: snd-pcm-oss ...
759 WARNING: Error inserting snd_mixer_oss
760 (/lib/modules/2.6.12-gentoo-r6/kernel/sound/core/oss/snd-mixer-oss.ko): Unknown
761 symbol in module, or unknown parameter (see dmesg) FATAL: Error inserting
762 snd_pcm_oss
763 (/lib/modules/2.6.12-gentoo-r6/kernel/sound/core/oss/snd-pcm-oss.ko): Unknown
764 symbol in module, or unknown parameter (see dmesg)
765 [ !! ]
766 * Loading: snd-mixer-oss ...
767 FATAL: Error inserting snd_mixer_oss
768 (/lib/modules/2.6.12-gentoo-r6/kernel/sound/core/oss/snd-mixer-oss.ko): Unknown
769 symbol in module, or unknown parameter (see dmesg)
770 [ !! ]
771 * Loading: snd-seq ... [ ok ]
772 * Loading: snd-emu10k1-synth ... [ ok ]
773 * Loading: snd-seq-midi ... [ ok ]
774 * Restoring Mixer Levels ... [ ok ]
775 </pre>
776
777 <p>
778 And when you take a look at <c>dmesg</c> as suggested, you're quite likely to
779 see:
780 </p>
781
782 <pre caption="dmesg output">
783 <comment>(Only relevant portions are shown below)</comment>
784 # <i>dmesg | less</i>
785 ACPI: PCI Interrupt 0000:02:06.0[A] -> Link [APC3] -> GSI 18 (level, low) -> IRQ 209
786 snd_mixer_oss: Unknown symbol snd_unregister_oss_device
787 snd_mixer_oss: Unknown symbol snd_register_oss_device
788 snd_mixer_oss: Unknown symbol snd_mixer_oss_notify_callback
789 snd_mixer_oss: Unknown symbol snd_oss_info_register
790 snd_pcm_oss: Unknown symbol snd_unregister_oss_device
791 snd_pcm_oss: Unknown symbol snd_register_oss_device
792 snd_pcm_oss: Unknown symbol snd_mixer_oss_ioctl_card
793 snd_pcm_oss: Unknown symbol snd_oss_info_register
794 snd_mixer_oss: Unknown symbol snd_unregister_oss_device
795 snd_mixer_oss: Unknown symbol snd_register_oss_device
796 snd_mixer_oss: Unknown symbol snd_mixer_oss_notify_callback
797 snd_mixer_oss: Unknown symbol snd_oss_info_register
798 </pre>
799
800 <p>
801 The above issue is caused when you switch from <c>alsa-driver</c> to in-kernel
802 ALSA because when you unmerge <c>alsa-driver</c> the module files are config
803 protected and hence get left behind. So, when you switch to in-kernel
804 drivers, running <c>modprobe</c> gives you a mix of <c>alsa-driver</c> and
805 in-kernel modules thus causing the above errors.
806 </p>
807
808 <p>
809 The solution is quite easy. We just need to manually remove the problem causing
810 directory after you unmerge <c>alsa-driver</c>. Be sure to remove the correct
811 kernel version and not the current one!
812 </p>
813
814 <pre caption="Removing the alsa-driver modules">
815 # <i>rm -rf /lib/modules/$(uname -r)/alsa-driver</i>
816 </pre>
817
818 <p>
819 Another reason for error messages similar to the ones above could be a file in
820 <path>/etc/modules.d</path> supplying a <c>device_mode</c> parameter when it
821 isn't required. Confirm that this is indeed the issue and find out which file
822 is the culprit.
823 </p>
824
825 <pre caption="Confirming and searching for device_mode">
826 <comment>(Check dmesg to confirm)</comment>
827 # <i>dmesg | grep device_mode</i>
828 snd: Unknown parameter `device_mode'
829 <comment>(Now, to get to the source of the issue)</comment>
830 # <i>grep device_mode /etc/modules.d/*</i>
831 </pre>
832
833 <p>
834 Usually it is a file called <path>alsa</path> with the line <c>options snd
835 device_mode=0666</c>. Remove this line and restart the alsasound service and
836 that should take care of this issue.
837 </p>
838
839 </body>
840 </section>
841 </chapter>
842
843 <chapter>
844 <title>Other things ALSA</title>
845 <section id="midi">
846 <title>Setting up MIDI support</title>
847 <body>
848
849 <p>
850 First, check to make sure that you enabled the <c>midi</c> USE flag in
851 <path>/etc/make.conf</path>.
852 </p>
853
854 <pre caption="MIDI support in /etc/make.conf">
855 USE="midi"
856 </pre>
857
858 <p>
859 If you didn't previously enable <c>midi</c>, go ahead and add it to
860 <path>/etc/make.conf</path> now. You will also need to re-emerge any ALSA
861 packages that use the <c>midi</c> flag, such as <c>alsa-lib</c>,
862 <c>alsa-utils</c>, and <c>alsa-driver</c>.
863 </p>
864
865 <p>
866 If your sound card is one of those that come with on-board MIDI synthesizers
867 and you would like to listen to some .mid files, you have to install
868 <c>awesfx</c> which is basically a set of utilities for controlling the AWE32
869 driver. We need to install it first. If you don't have a hardware synthesizer,
870 you can use a virtual one. Please see the section on
871 <uri link="#vsynth">Virtual Synthesizers</uri> for more information.
872 </p>
873
874 <pre caption="Installing awesfx">
875 # <i>emerge awesfx</i>
876 </pre>
877
878 <note>
879 You will need to copy over SoundFont (SF2) files from your sound card's driver
880 CD or a Windows installation into <path>/usr/share/sounds/sf2/</path>. For
881 example a sound font file for the Creative SBLive! card would be 8MBGMSFX.SF2.
882 </note>
883
884 <p>
885 After copying over the Soundfont files, we can then play a midi file as shown.
886 You can also add the <c>asfxload</c> command to
887 <path>/etc/conf.d/local.start</path>, so that the sound font is loaded
888 every time the system starts up.
889 </p>
890
891 <note>
892 <path>/mnt</path> paths mentioned in the code listing(s) below will <e>not</e>
893 be the same in your machine. They are just an example. Please be careful to
894 change the path to suit your machine.
895 </note>
896
897 <pre caption="Loading Soundfonts">
898 <comment>(First, copy the Soundfont)</comment>
899 # <i>cp /mnt/win2k/Program\ Files/CreativeSBLive2k/SFBank/8MBGMSFX.SF2 /usr/share/sounds/sf2/</i>
900 <comment>(Or get it from your SoundBlaster CD)</comment>
901 # <i>cp /mnt/cdrom/AUDIO/ENGLISH/SFBANK/8MBGMSFX.SF2 /usr/share/sounds/sf2/</i>
902 <comment>(We load the specific Soundfont)</comment>
903 # <i>asfxload /usr/share/sounds/sf2/8MBGMSFX.SF2</i>
904 </pre>
905
906 <p>
907 You can now play midi files using a program like <c>aplaymidi</c>. Run
908 <c>aplaymidi -l</c> to get a list of available ports and then pick one
909 to play the file on.
910 </p>
911
912 <pre caption="Playing MIDI">
913 <comment>(Check open ports)</comment>
914 # <i>aplaymidi -l</i>
915 Port Client name Port name
916 64:0 EMU10K1 MPU-401 (UART) EMU10K1 MPU-401 (UART)
917 65:0 Emu10k1 WaveTable Emu10k1 Port 0
918 65:1 Emu10k1 WaveTable Emu10k1 Port 1
919 65:2 Emu10k1 WaveTable Emu10k1 Port 2
920 65:3 Emu10k1 WaveTable Emu10k1 Port 3
921 <comment>(Pick a port, and play a mid file)</comment>
922 # <i> aplaymidi --port=65:0 /mnt/shyam/music/midi/mi2.mid</i>
923 </pre>
924
925 </body>
926 </section>
927 <section id="vsynth">
928 <title>Virtual Synthesizers</title>
929 <body>
930
931 <p>
932 If your sound card lacks a hardware synthesizer, you could use a virtual one
933 like <c>timidity++</c>. Installation is a breeze.
934 </p>
935
936 <pre caption="Installing timidity++">
937 # <i>emerge timidity++</i>
938 </pre>
939
940 <p>
941 For timidity to play sounds, it needs a sound font. Fortunately, the ebuild will
942 install some sound font packages for you. There are a few other font packages
943 available in Portage, such as <c>timidity-freepats</c> and
944 <c>timidity-eawpatches</c>. You can have multiple sound font configurations
945 installed, and you can place your own in <path>/usr/share/timidity/</path>. To
946 switch between different timidity configurations, you should use
947 <c>eselect</c>.
948 </p>
949
950 <pre caption="Changing configurations">
951 # <i>eselect timidity list</i>
952 # <i>eselect timidity set eawpatches</i>
953 </pre>
954
955 <p>
956 Don't forget to add <c>timidity</c> to the default runlevel.
957 </p>
958
959 <pre caption="Adding timidity to the default runlevel">
960 # <i>rc-update add timidity default</i>
961 # <i>/etc/init.d/timidity start</i>
962 </pre>
963
964 <p>
965 You can now try out <uri link="#doc_chap4_pre3">Playing MIDI</uri> files.
966 </p>
967
968 </body>
969 </section>
970 <section>
971 <title>Tools and Firmware</title>
972 <body>
973
974 <p>
975 Some specific sound cards can benefit from certain tools provided by the
976 <c>alsa-tools</c> and <c>alsa-firmware</c> packages. You may install either with
977 a simple <c>emerge</c>.
978 </p>
979
980 <pre caption="Installing ALSA Tools">
981 # <i>emerge alsa-tools</i>
982 </pre>
983
984 </body>
985 </section>
986 <section>
987 <title>Multiple sound cards</title>
988 <body>
989
990 <p>
991 You can more than one sound card in your system simultaneously, provided that
992 you have built ALSA as modules in your kernel (or have installed
993 <c>alsa-driver</c> instead). You just need to specify which should be started
994 first in <path>/etc/modules.d/alsa</path>. Your cards are identified by their
995 driver names inside this file. 0 is the first card, 1 is the second, and so on.
996 Here's an example for a system with two sound cards.
997 </p>
998
999 <pre caption="Two sound cards in /etc/modules.d/alsa">
1000 options snd-emu10k1 index=0
1001 options snd-via82xx index=1
1002 </pre>
1003
1004 <p>
1005 Or, if you have two cards that use the same driver, you specify them on the same
1006 line, using comma-separated numbers. Here's an example for a system with three
1007 sound cards, two of which are the same Intel High Definition Audio card.
1008 </p>
1009
1010 <pre caption="Multiple sound cards in /etc/modules.d/alsa">
1011 options snd-ymfpci index=0
1012 options snd-hda-intel index=1,2
1013 </pre>
1014
1015 </body>
1016 </section>
1017 <section>
1018 <title>Plugins</title>
1019 <body>
1020
1021 <p>
1022 You may want to install some plugins for extra functionality.
1023 <c>alsa-plugins</c> is a collection of useful plugins, which include: PulseAudio
1024 output, a sample rate converter, jack (a low-latency audio server), and an
1025 encoder that lets you output 6-channel audio through digital S/PDIF connections
1026 (both optical and coaxial). You can choose which of its plugins you want
1027 installed by adding their USE flags to <path>/etc/portage/package.use</path>.
1028 </p>
1029
1030 <pre caption="Installing alsa-plugins">
1031 # <i>emerge -avt alsa-plugins</i>
1032 </pre>
1033
1034 </body>
1035 </section>
1036 <section>
1037 <title>A big thank you to...</title>
1038 <body>
1039
1040 <p>
1041 Everyone who contributed to the earlier version of the Gentoo ALSA Guide:
1042 Vincent Verleye, Grant Goodyear, Arcady Genkin, Jeremy Huddleston,
1043 John P. Davis, Sven Vermeulen, Benny Chuang, Tiemo Kieft and Erwin.
1044 </p>
1045
1046 </body>
1047 </section>
1048 <section>
1049 <title>References</title>
1050 <body>
1051
1052 <ul>
1053 <li><uri link="http://www.alsa-project.org/">The ALSA Project</uri></li>
1054 <li><uri link="http://linux-sound.org">Linux Sound/MIDI Software</uri></li>
1055 </ul>
1056
1057 </body>
1058 </section>
1059 </chapter>
1060 </guide>

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