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Revision 1.81 - (show annotations) (download) (as text)
Wed Mar 5 09:16:49 2008 UTC (6 years, 5 months ago) by nightmorph
Branch: MAIN
Changes since 1.80: +40 -220 lines
File MIME type: application/xml
removed alsa-driver steps from the guide, per bug 183418, bug 207427 and other showstopper/regression bugs, and requests from the alsa & kernel teams. no one maintains or wants to maintain alsa-driver. it is the weakest link.

1 <?xml version='1.0' encoding="UTF-8"?>
2 <!-- $Header: /var/cvsroot/gentoo/xml/htdocs/doc/en/alsa-guide.xml,v 1.80 2007/05/19 03:00:29 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>2.23</version>
28 <date>2008-03-05</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 Historically, Gentoo offered two ways to get ALSA up and running: the
60 <e>in-kernel</e> driver and the external <c>alsa-driver</c> package. The two
61 solutions essentially do the same thing; this made supporting the external
62 package extremely difficult and time-consuming. The Gentoo maintainers decided
63 to discontinue support for the <c>alsa-driver</c> package, concentrating their
64 resources on the ALSA drivers available within the Linux kernel. This guide will
65 focus solely on configuring ALSA via the in-kernel driver.
66 </p>
67
68 <p>
69 If you still require the <c>alsa-driver</c> package, please email the <mail
70 link="alsa-bugs@gentoo.org">Gentoo ALSA maintainers</mail> with why the
71 in-kernel drivers don't work for you. Be sure to include detailed error logs.
72 </p>
73
74 </body>
75 </section>
76 </chapter>
77
78 <chapter>
79 <title>Installing ALSA</title>
80 <section id="lspci">
81 <title>Before you proceed</title>
82 <body>
83
84 <p>
85 First, you need to know what drivers your sound card uses. In most cases, sound
86 cards (onboard and otherwise) are PCI based and <c>lspci</c> will help you in
87 digging out the required information. Please <c>emerge sys-apps/pciutils</c> to
88 get <c>lspci</c>, if you don't have it installed already. In case you have a USB
89 sound card, <c>lsusb</c> from <c>sys-apps/usbutils</c> <e>might</e> be of help.
90 For ISA cards, try using <c>sys-apps/isapnptools</c>. Also, the following pages
91 <e>may</e> help users with ISA based sound cards:
92 </p>
93
94 <ul>
95 <li>
96 <uri link="http://www.roestock.demon.co.uk/isapnptools/">The ISAPNPTOOLS
97 Page</uri>
98 </li>
99 <li>
100 <uri link="http://www2.linuxjournal.com/article/3269">LinuxJournal PnP
101 Article</uri>
102 </li>
103 <li>
104 <uri link="http://www.tldp.org/HOWTO/Sound-HOWTO/x320.html">TLDP Sound
105 HowTo</uri>
106 </li>
107 </ul>
108
109 <note>
110 For ease of use/explanation, we assume the user has a PCI based sound card for
111 the remainder of this guide.
112 </note>
113
114 <p>
115 We now proceed to find out details about the sound card.
116 </p>
117
118 <pre caption="Soundcard Details">
119 # <i>lspci -v | grep -i audio</i>
120 0000:00:0a.0 Multimedia audio controller: Creative Labs SB Live! EMU10k1 (rev 06)
121 </pre>
122
123 <p>
124 We now know that the sound card on the machine is a Sound Blaster Live! and the
125 card manufacturer is Creative Labs. Head over to the <uri
126 link="http://bugtrack.alsa-project.org/main/index.php/Matrix:Main">ALSA
127 Soundcard Matrix</uri> page and select Creative Labs from the list. You will
128 be taken to the Creative Labs matrix page where you can see that the SB Live!
129 uses the <c>emu10k1</c> module. That is the information we need for now. If
130 you are interested in detailed information, you can click on the link next to
131 the "Details" and that will take you to the <c>emu10k1</c> specific page.
132 </p>
133
134 <p>
135 If you intend to use MIDI, then you should add <c>midi</c> to your USE flags in
136 <path>/etc/make.conf</path> before emerging any ALSA packages. Later in the
137 guide, we will show you how to set up <uri link="#midi">MIDI support</uri>.
138 </p>
139
140 </body>
141 </section>
142 <section id="kernel">
143 <title>Configuring the kernel</title>
144 <body>
145
146 <note>
147 Since the 2005.0 release, Gentoo Linux uses 2.6 as the default kernel. Please
148 check that your kernel is a 2.6 series kernel. This method will <e>not</e> work
149 on a 2.4 kernel.
150 </note>
151
152 <p>
153 Let us now configure the kernel to enable ALSA.
154 </p>
155
156 <impo>
157 <c>genkernel</c> users should now run <c>genkernel --menuconfig all</c> and
158 then follow the instructions in <uri link="#doc_chap2_pre3">Kernel Options for
159 ALSA</uri>.
160 </impo>
161
162 <pre caption="Heading over to the source">
163 # <i>cd /usr/src/linux</i>
164 # <i>make menuconfig</i>
165 </pre>
166
167 <note>
168 The above example assumes that <path>/usr/src/linux</path> symlink points to
169 the kernel sources you want to use. Please ensure the same before proceeding.
170 </note>
171
172 <p>
173 Now we will look at some of the options we will have to enable in the 2.6
174 kernel to ensure proper ALSA support for our sound card.
175 </p>
176
177 <p>
178 Please note that for ease of use, all examples show ALSA built as modules. It
179 is advisable to follow the same as it then allows the use of <c>alsaconf</c>
180 which is a boon when you want to configure your card. Please do <e>not</e> skip
181 the <uri link="#alsa-config">Configuration</uri> section of this document. If
182 you still like to have options built-in, ensure that you make changes to your
183 config accordingly.
184 </p>
185
186 <pre caption="Kernel Options for ALSA">
187 Device Drivers ---&gt;
188 Sound ---&gt;
189
190 <comment>(This needs to be enabled)</comment>
191 &lt;M&gt; Sound card support
192
193 <comment>(Make sure OSS is disabled)</comment>
194 Open Sound System ---&gt;
195 &lt; &gt; Open Sound System (DEPRECATED)
196
197 <comment>(Move one step back and enter ALSA)</comment>
198 Advanced Linux Sound Architecture ---&gt;
199 &lt;M&gt; Advanced Linux Sound Architecture
200 <comment>(Select this if you want MIDI sequencing and routing)</comment>
201 &lt;M&gt; Sequencer support
202 <comment>(Old style /dev/mixer* and /dev/dsp* support. Recommended.)</comment>
203 &lt;M&gt; OSS Mixer API
204 &lt;M&gt; OSS PCM (digital audio) API
205
206 <comment>(You now have a choice of devices to enable support for. Generally,
207 you will have one type of device and not more. If you have more than one
208 sound card, please enable them all here.)</comment>
209
210 <comment>(Mostly for testing and development purposes, not needed for normal
211 users unless you know what you are doing.)</comment>
212 Generic devices ---&gt;
213
214 <comment>(For ISA Sound cards)</comment>
215 ISA devices ---&gt;
216 <comment>(IF you had the Gravis, you would select this option)</comment>
217 &lt;M&gt; Gravis UltraSound Extreme
218
219 <comment>(Move one level back and into PCI devices. Most sound cards today are
220 PCI devices)</comment>
221 PCI devices ---&gt;
222 <comment>(We now select the emu10k1 driver for our card)</comment>
223 &lt;M&gt; Emu10k1 (SB Live!, Audigy, E-mu APS)
224 <comment>(Or an Intel card would be)</comment>
225 &lt;M&gt; Intel/SiS/nVidia/AMD/ALi AC97 Controller
226 <comment>(Or if you have a VIA Card)</comment>
227 &lt;M&gt; VIA 82C686A/B, 8233/8235 AC97 Controller
228
229 <comment>(Move one level back and select in case you have an USB sound card)</comment>
230 USB Devices ---&gt;
231 </pre>
232
233 <p>
234 Now that your options are set, you can (re)compile the kernel and ALSA support
235 for your card should be functional once you reboot into the new kernel. Don't
236 forget to update your GRUB configuration to use the newly built kernel.
237 You can now proceed to <uri link="#alsa-utilities">ALSA Utilities</uri> and
238 see if everything is working as it should.
239 </p>
240
241 </body>
242 </section>
243 </chapter>
244
245 <chapter>
246 <title>Configuring/Testing ALSA</title>
247 <section id="alsa-utilities">
248 <title>ALSA Utilities</title>
249 <body>
250
251 <p>
252 <c>alsa-utils</c> forms an integral part of ALSA as it has a truckload of
253 programs that are highly useful, including the ALSA Initscripts. Hence we
254 strongly recommend that you install <c>alsa-utils</c>
255 </p>
256
257 <pre caption="Install alsa-utils">
258 # <i>emerge alsa-utils</i>
259 </pre>
260
261 <note>
262 If you did <e>not</e> compile ALSA as modules, please proceed to the <uri
263 link="#initscript">ALSA Initscript</uri> section. The rest of you need to
264 configure ALSA. This is made very easy by the existence of the <c>alsaconf</c>
265 tool provided by <c>alsa-utils</c>.
266 </note>
267
268 </body>
269 </section>
270 <section id="alsa-config">
271 <title>Configuration</title>
272 <body>
273
274 <p>
275 Recent versions of <c>udev</c> (<c>>=udev-103</c>) provide some degree of
276 kernel-level autoconfiguration of your sound card. If possible, try to rely on
277 just letting your kernel automatically setup your sound card for you. Otherwise,
278 use <c>alsaconf</c> to configure your card, as shown below.
279 </p>
280
281 <note>
282 Please shut down any programs that <e>might</e> access the sound card while
283 running <c>alsaconf</c>.
284 </note>
285
286 <p>
287 To configure your sound card just type <c>alsaconf</c> in a shell as root.
288 </p>
289
290 <pre caption="Invoking alsaconf">
291 # <i>alsaconf</i>
292 </pre>
293
294 <p>
295 You will now see a neat menu guided interface that will automatically probe
296 your devices and try to find out your sound card. You will be asked to pick
297 your sound card from a list. Once that's done, it will ask you permission to
298 automatically make required changes to <path>/etc/modules.d/alsa</path>.
299 It will then adjust your volume settings to optimum levels, run
300 <c>update-modules</c> and start the <path>/etc/init.d/alsasound</path> service.
301 Once <c>alsaconf</c> exits, you can proceed with setting up the ALSA
302 initscript.
303 </p>
304
305 </body>
306 </section>
307 <section id="initscript">
308 <title>ALSA Initscript</title>
309 <body>
310
311 <p>
312 We're now almost all setup. Whichever method you chose to install ALSA, you'll
313 need to have something load your modules or initialize ALSA and restore your
314 volume settings when your system comes up. The ALSA Initscript handles all of
315 this for you and is called <c>alsasound</c>. Add it to the boot runlevel.
316 </p>
317
318 <pre caption="Adding ALSA to the boot runlevel">
319 # <i>rc-update add alsasound boot</i>
320 * alsasound added to runlevel boot
321 * rc-update complete.
322 </pre>
323
324 <p>
325 Next, just check the <path>/etc/conf.d/alsasound</path> file and ensure that
326 SAVE_ON_STOP variable is set to yes. This saves your sound settings when you
327 shutdown your system.
328 </p>
329
330 </body>
331 </section>
332 <section>
333 <title>Audio Group</title>
334 <body>
335
336 <p>
337 Before we move on to testing, there's one last <e>important</e> thing that needs
338 to be setup. Rule of thumb in a *nix OS: Do not run as root unless needed.
339 This applies here as well ;) How? Well, most of the times you should be logged
340 in as a user and would like to listen to music or access your soundcard. For
341 that to happen, you need to be in the "audio" group. At this point, we'll add
342 users to the audio group, so that they won't have any issues when they want to
343 access sound devices. We'll use <c>gpasswd</c> here and you need to be logged in
344 as root for this to work.
345 </p>
346
347 <pre caption="Adding users to the audio group">
348 <comment>(Substitute &lt;username&gt; with your user)</comment>
349 # <i>gpasswd -a &lt;username&gt; audio </i>
350 Adding user &lt;username&gt; to group audio
351 </pre>
352
353 </body>
354 </section>
355 <section>
356 <title>Volume Check!</title>
357 <body>
358
359 <p>
360 We've completed all the setups and prerequisites, so let's fire up ALSA. If
361 you ran <c>alsaconf</c>, you can skip this step, since <c>alsaconf</c> already
362 does this for you.
363 </p>
364
365 <pre caption="Start the service">
366 # <i>/etc/init.d/alsasound start</i>
367 </pre>
368
369 <p>
370 Now that the required things have been taken care of, we need to check up on
371 the volume as in certain cases, it is muted. We use <c>alsamixer</c> for this
372 purpose.
373 </p>
374
375 <pre caption="Starting alsamixer">
376 <comment>(Opens up a console program. Only required settings are shown)</comment>
377 # <i>alsamixer</i>
378 </pre>
379
380 <impo>
381 If you have issues starting up <c>alsamixer</c> and get errors such as
382 alsamixer: function snd_ctl_open failed for default: No such file or directory,
383 this is usually an issue with udev setting up the devices. Run <c>killall
384 udevd; udevstart</c> to reload <path>/dev</path> entries and fire up
385 <c>alsamixer</c>. It should solve the issue.
386 </impo>
387
388 <p>
389 This is how the ALSA Mixer <e>might</e> look the first time you open it. Pay
390 attention to the Master and PCM channels which both have an MM below them.
391 That means they are muted. If you try to play anything with <c>alsamixer</c>
392 in this state, you will not hear anything on your speakers.
393 </p>
394
395 <figure link="/images/docs/alsa-mixermuted.png" short="AlsaMixer Muted" caption="The Alsa Mixer Main Window, Muted"/>
396
397 <p>
398 Now, we shall unmute the channels, and set volume levels as needed.
399 </p>
400
401 <warn>
402 Both Master <e>and</e> PCM need to be unmuted and set to audible volume levels
403 if you want to hear some output on your speakers.
404 </warn>
405
406 <ul>
407 <li>
408 To move between channels, use your left and right arrow keys. (&lt;-
409 &amp; -&gt;)
410 </li>
411 <li>
412 To toggle mute, move to the specific channel, for example Master and press
413 the <e>m</e> key on the keyboard.
414 </li>
415 <li>
416 To increase and decrease the volume levels, use the up and down arrow keys
417 respectively.
418 </li>
419 </ul>
420
421 <note>
422 Be careful when setting your Bass and Treble values. 50 is usually a good
423 number for both. Extremely high values of Bass may cause <e>jarring</e>
424 on speakers that are not designed to handle them.
425 </note>
426
427 <p>
428 After you're all done, your ALSA Mixer should look similar to the one below.
429 Note the 00 instead of the MM and also the volume levels for some optimum
430 settings.
431 </p>
432
433 <figure link="/images/docs/alsa-mixerunmuted.png" short="AlsaMixer Unmuted" caption="Alsa Mixer ready to roll"/>
434
435 </body>
436 </section>
437 <section>
438 <title>Sound Check!</title>
439 <body>
440
441 <p>
442 Finally. Some music. If everything above is perfect, you should now be able to
443 listen to some good music. A quick way to test is to use a command line tool
444 like <c>media-sound/madplay</c>. You could also use something more well known
445 like <c>mpg123</c>. If you are an ogg fan, you could use <c>ogg123</c> provided
446 by <c>media-sound/vorbis-tools</c>. Use any player you are comfortable with. As
447 always, <c>emerge</c> what you need.
448 </p>
449
450 <pre caption="Getting the software">
451 <comment>(Install the applications you want)</comment>
452 # <i>emerge madplay mpg123</i>
453 <comment>(To play .ogg files)</comment>
454 # <i>emerge vorbis-tools</i>
455 </pre>
456
457 <p>
458 And then play your favorite sound track...
459 </p>
460
461 <pre caption="Playing Music">
462 # <i>madplay -v /mnt/shyam/Music/Paul\ Oakenfold\ -\ Dread\ Rock.mp3</i>
463 MPEG Audio Decoder 0.15.2 (beta) - Copyright (C) 2000-2004 Robert Leslie et al.
464 Title: Dread Rock
465 Artist: Paul Oakenfold
466 Album: Matrix Reloaded
467 Year: 2003
468 Genre: Soundtrack
469 Soundtrack
470 00:04:19 Layer III, 160 kbps, 44100 Hz, joint stereo (MS), no CRC
471
472 # <i>ogg123 Paul\ Oakenfold\ -\ Dread\ Rock.ogg</i>
473 Audio Device: Advanced Linux Sound Architecture (ALSA) output
474
475 Playing: Paul Oakenfold - Dread Rock.ogg
476 Ogg Vorbis stream: 2 channel, 44100 Hz
477 Genre: Soundtrack
478 Transcoded: mp3;160
479 Title: Dread Rock
480 Artist: Paul Oakenfold
481 Date: 2003
482 Album: Matrix Reloaded
483 Time: 00:11.31 [04:28.75] of 04:40.06 (200.6 kbps) Output Buffer 96.9%
484 </pre>
485
486 </body>
487 </section>
488 <section>
489 <title>ALSA and USE</title>
490 <body>
491
492 <p>
493 You can now add the <c>alsa</c> use flag to <path>/etc/make.conf</path> to
494 ensure that your applications that support ALSA get built with it. Some
495 architectures like x86 and amd64 have the flag enabled by default.
496 </p>
497
498 </body>
499 </section>
500 <section>
501 <title>Issues?</title>
502 <body>
503
504 <p>
505 If for some reason you're unable to hear sound, the first thing to do would
506 be to check your <uri link="#doc_chap3_pre6">alsamixer</uri> settings. 80% of
507 the issues lie with muted channels or low volume. Also check your Window
508 Manager's sound applet and verify that volumes are set to audible levels.
509 </p>
510
511 <p>
512 <path>/proc</path> is your friend. And in this case, <path>/proc/asound</path>
513 is your best friend. We shall just take a short look at how much info is made
514 available to us there.
515 </p>
516
517 <pre caption="Fun with /proc/asound">
518 <comment>(First and foremost, if /proc/asound/cards shows your card, ALSA has
519 picked up your sound card fine.)</comment>
520 # <i>cat /proc/asound/cards</i>
521 0 [Live ]: EMU10K1 - Sound Blaster Live!
522 Sound Blaster Live! (rev.6, serial:0x80271102) at 0xb800, irq 11
523
524 <comment>(This displays the current running ALSA version)</comment>
525 # <i>cat /proc/asound/version</i>
526 Advanced Linux Sound Architecture Driver Version 1.0.8 (Thu Jan 13 09:39:32 2005 UTC).
527
528 <comment>(ALSA OSS emulation details)</comment>
529 # <i>cat /proc/asound/oss/sndstat</i>
530 Sound Driver:3.8.1a-980706 (ALSA v1.0.8 emulation code)
531 Kernel: Linux airwolf.zion 2.6.11ac1 #2 Wed May 4 00:35:08 IST 2005 i686
532 Config options: 0
533
534 Installed drivers:
535 Type 10: ALSA emulation
536
537 Card config:
538 Sound Blaster Live! (rev.6, serial:0x80271102) at 0xb800, irq 11
539
540 Audio devices:
541 0: EMU10K1 (DUPLEX)
542
543 Synth devices: NOT ENABLED IN CONFIG
544
545 Midi devices:
546 0: EMU10K1 MPU-401 (UART)
547
548 Timers:
549 7: system timer
550
551 Mixers:
552 0: SigmaTel STAC9721/23
553 </pre>
554
555 <!-- TODO: remove this a few months after alsa-driver leaves the tree -->
556
557 <p>
558 The other most common issue users face is the dreaded "Unknown symbol in module"
559 error. An example of the same is shown below.
560 </p>
561
562 <pre caption="Unknown Symbol in module error">
563 # <i>/etc/init.d/alsasound start</i>
564 * Loading ALSA modules ...
565 * Loading: snd-card-0 ... [ ok ]
566 * Loading: snd-pcm-oss ...
567 WARNING: Error inserting snd_mixer_oss
568 (/lib/modules/2.6.12-gentoo-r6/kernel/sound/core/oss/snd-mixer-oss.ko): Unknown
569 symbol in module, or unknown parameter (see dmesg) FATAL: Error inserting
570 snd_pcm_oss
571 (/lib/modules/2.6.12-gentoo-r6/kernel/sound/core/oss/snd-pcm-oss.ko): Unknown
572 symbol in module, or unknown parameter (see dmesg)
573 [ !! ]
574 * Loading: snd-mixer-oss ...
575 FATAL: Error inserting snd_mixer_oss
576 (/lib/modules/2.6.12-gentoo-r6/kernel/sound/core/oss/snd-mixer-oss.ko): Unknown
577 symbol in module, or unknown parameter (see dmesg)
578 [ !! ]
579 * Loading: snd-seq ... [ ok ]
580 * Loading: snd-emu10k1-synth ... [ ok ]
581 * Loading: snd-seq-midi ... [ ok ]
582 * Restoring Mixer Levels ... [ ok ]
583 </pre>
584
585 <p>
586 And when you take a look at <c>dmesg</c> as suggested, you're quite likely to
587 see:
588 </p>
589
590 <pre caption="dmesg output">
591 <comment>(Only relevant portions are shown below)</comment>
592 # <i>dmesg | less</i>
593 ACPI: PCI Interrupt 0000:02:06.0[A] -> Link [APC3] -> GSI 18 (level, low) -> IRQ 209
594 snd_mixer_oss: Unknown symbol snd_unregister_oss_device
595 snd_mixer_oss: Unknown symbol snd_register_oss_device
596 snd_mixer_oss: Unknown symbol snd_mixer_oss_notify_callback
597 snd_mixer_oss: Unknown symbol snd_oss_info_register
598 snd_pcm_oss: Unknown symbol snd_unregister_oss_device
599 snd_pcm_oss: Unknown symbol snd_register_oss_device
600 snd_pcm_oss: Unknown symbol snd_mixer_oss_ioctl_card
601 snd_pcm_oss: Unknown symbol snd_oss_info_register
602 snd_mixer_oss: Unknown symbol snd_unregister_oss_device
603 snd_mixer_oss: Unknown symbol snd_register_oss_device
604 snd_mixer_oss: Unknown symbol snd_mixer_oss_notify_callback
605 snd_mixer_oss: Unknown symbol snd_oss_info_register
606 </pre>
607
608 <p>
609 The above issue is caused when you switch from the <c>alsa-driver</c> to in-kernel
610 ALSA because when you unmerge <c>alsa-driver</c> the module files are config
611 protected and hence get left behind. So, when you switch to in-kernel
612 drivers, running <c>modprobe</c> gives you a mix of <c>alsa-driver</c> and
613 in-kernel modules thus causing the above errors.
614 </p>
615
616 <p>
617 The solution is quite easy. We just need to manually remove the problem causing
618 directory after you unmerge <c>alsa-driver</c>. Be sure to remove the correct
619 kernel version and not the current one!
620 </p>
621
622 <pre caption="Removing the alsa-driver modules">
623 # <i>rm -rf /lib/modules/$(uname -r)/alsa-driver</i>
624 </pre>
625
626 <p>
627 Another reason for error messages similar to the ones above could be a file in
628 <path>/etc/modules.d</path> supplying a <c>device_mode</c> parameter when it
629 isn't required. Confirm that this is indeed the issue and find out which file
630 is the culprit.
631 </p>
632
633 <pre caption="Confirming and searching for device_mode">
634 <comment>(Check dmesg to confirm)</comment>
635 # <i>dmesg | grep device_mode</i>
636 snd: Unknown parameter `device_mode'
637 <comment>(Now, to get to the source of the issue)</comment>
638 # <i>grep device_mode /etc/modules.d/*</i>
639 </pre>
640
641 <p>
642 Usually it is a file called <path>alsa</path> with the line <c>options snd
643 device_mode=0666</c>. Remove this line and restart the <c>alsasound</c> service
644 and that should take care of this issue.
645 </p>
646
647 <!-- End of removal notice -->
648
649 </body>
650 </section>
651 </chapter>
652
653 <chapter>
654 <title>Other things ALSA</title>
655 <section id="midi">
656 <title>Setting up MIDI support</title>
657 <body>
658
659 <p>
660 First, check to make sure that you enabled the <c>midi</c> USE flag in
661 <path>/etc/make.conf</path>. If you didn't, go ahead and add it now. You will
662 also need to re-emerge any ALSA packages that use the <c>midi</c> flag, such as
663 <c>alsa-lib</c> and <c>alsa-utils</c>.
664 </p>
665
666 <p>
667 If your sound card is one of those that come with on-board MIDI synthesizers
668 and you would like to listen to some .mid files, you have to install
669 <c>awesfx</c> which is basically a set of utilities for controlling the AWE32
670 driver. We need to install it first. If you don't have a hardware synthesizer,
671 you can use a virtual one. Please see the section on
672 <uri link="#vsynth">Virtual Synthesizers</uri> for more information.
673 </p>
674
675 <pre caption="Installing awesfx">
676 # <i>emerge awesfx</i>
677 </pre>
678
679 <note>
680 You will need to copy over SoundFont (SF2) files from your sound card's driver
681 CD or a Windows installation into <path>/usr/share/sounds/sf2/</path>. For
682 example a sound font file for the Creative SBLive! card would be 8MBGMSFX.SF2.
683 </note>
684
685 <p>
686 After copying over the Soundfont files, we can then play a midi file as shown.
687 You can also add the <c>asfxload</c> command to
688 <path>/etc/conf.d/local.start</path>, so that the sound font is loaded
689 every time the system starts up.
690 </p>
691
692 <note>
693 <path>/mnt</path> paths mentioned in the code listing(s) below will <e>not</e>
694 be the same in your machine. They are just an example. Please be careful to
695 change the path to suit your machine.
696 </note>
697
698 <pre caption="Loading Soundfonts">
699 <comment>(First, copy the Soundfont)</comment>
700 # <i>cp /mnt/win2k/Program\ Files/CreativeSBLive2k/SFBank/8MBGMSFX.SF2 /usr/share/sounds/sf2/</i>
701 <comment>(Or get it from your SoundBlaster CD)</comment>
702 # <i>cp /mnt/cdrom/AUDIO/ENGLISH/SFBANK/8MBGMSFX.SF2 /usr/share/sounds/sf2/</i>
703 <comment>(We load the specific Soundfont)</comment>
704 # <i>asfxload /usr/share/sounds/sf2/8MBGMSFX.SF2</i>
705 </pre>
706
707 <p>
708 You can now play midi files using a program like <c>aplaymidi</c>. Run
709 <c>aplaymidi -l</c> to get a list of available ports and then pick one
710 to play the file on.
711 </p>
712
713 <pre caption="Playing MIDI">
714 <comment>(Check open ports)</comment>
715 # <i>aplaymidi -l</i>
716 Port Client name Port name
717 64:0 EMU10K1 MPU-401 (UART) EMU10K1 MPU-401 (UART)
718 65:0 Emu10k1 WaveTable Emu10k1 Port 0
719 65:1 Emu10k1 WaveTable Emu10k1 Port 1
720 65:2 Emu10k1 WaveTable Emu10k1 Port 2
721 65:3 Emu10k1 WaveTable Emu10k1 Port 3
722 <comment>(Pick a port, and play a mid file)</comment>
723 # <i> aplaymidi --port=65:0 /mnt/shyam/music/midi/mi2.mid</i>
724 </pre>
725
726 </body>
727 </section>
728 <section id="vsynth">
729 <title>Virtual Synthesizers</title>
730 <body>
731
732 <p>
733 If your sound card lacks a hardware synthesizer, you could use a virtual one
734 like <c>timidity++</c>. Installation is a breeze.
735 </p>
736
737 <pre caption="Installing timidity++">
738 # <i>emerge timidity++</i>
739 </pre>
740
741 <p>
742 For timidity to play sounds, it needs a sound font. Fortunately, the ebuild will
743 install some sound font packages for you. There are a few other font packages
744 available in Portage, such as <c>timidity-freepats</c> and
745 <c>timidity-eawpatches</c>. You can have multiple sound font configurations
746 installed, and you can place your own in <path>/usr/share/timidity/</path>. To
747 switch between different timidity configurations, you should use
748 <c>eselect</c>.
749 </p>
750
751 <pre caption="Changing configurations">
752 # <i>eselect timidity list</i>
753 # <i>eselect timidity set eawpatches</i>
754 </pre>
755
756 <p>
757 Don't forget to add <c>timidity</c> to the default runlevel.
758 </p>
759
760 <pre caption="Adding timidity to the default runlevel">
761 # <i>rc-update add timidity default</i>
762 # <i>/etc/init.d/timidity start</i>
763 </pre>
764
765 <p>
766 You can now try out <uri link="#doc_chap4_pre3">Playing MIDI</uri> files.
767 </p>
768
769 </body>
770 </section>
771 <section>
772 <title>Tools and Firmware</title>
773 <body>
774
775 <p>
776 Some specific sound cards can benefit from certain tools provided by the
777 <c>alsa-tools</c> and <c>alsa-firmware</c> packages. You may install either with
778 a simple <c>emerge</c>.
779 </p>
780
781 <pre caption="Installing ALSA Tools">
782 # <i>emerge alsa-tools</i>
783 </pre>
784
785 </body>
786 </section>
787 <section>
788 <title>Multiple sound cards</title>
789 <body>
790
791 <p>
792 You can have more than one sound card in your system simultaneously, provided
793 that you have built ALSA as modules in your kernel. You just need to specify
794 which should be started first in <path>/etc/modules.d/alsa</path>. Your cards
795 are identified by their driver names inside this file. 0 is the first card, 1 is
796 the second, and so on. Here's an example for a system with two sound cards.
797 </p>
798
799 <pre caption="Two sound cards in /etc/modules.d/alsa">
800 options snd-emu10k1 index=0
801 options snd-via82xx index=1
802 </pre>
803
804 <p>
805 Or, if you have two cards that use the same driver, you specify them on the same
806 line, using comma-separated numbers. Here's an example for a system with three
807 sound cards, two of which are the same Intel High Definition Audio card.
808 </p>
809
810 <pre caption="Multiple sound cards in /etc/modules.d/alsa">
811 options snd-ymfpci index=0
812 options snd-hda-intel index=1,2
813 </pre>
814
815 </body>
816 </section>
817 <section>
818 <title>Plugins</title>
819 <body>
820
821 <p>
822 You may want to install some plugins for extra functionality.
823 <c>alsa-plugins</c> is a collection of useful plugins, which include: PulseAudio
824 output, a sample rate converter, jack (a low-latency audio server), and an
825 encoder that lets you output 6-channel audio through digital S/PDIF connections
826 (both optical and coaxial). You can choose which of its plugins you want
827 installed by adding their USE flags to <path>/etc/portage/package.use</path>.
828 </p>
829
830 <pre caption="Installing alsa-plugins">
831 # <i>emerge -avt alsa-plugins</i>
832 </pre>
833
834 </body>
835 </section>
836 <section>
837 <title>A big thank you to...</title>
838 <body>
839
840 <p>
841 Everyone who contributed to the earlier version of the Gentoo ALSA Guide:
842 Vincent Verleye, Grant Goodyear, Arcady Genkin, Jeremy Huddleston,
843 John P. Davis, Sven Vermeulen, Benny Chuang, Tiemo Kieft and Erwin.
844 </p>
845
846 </body>
847 </section>
848 <section>
849 <title>References</title>
850 <body>
851
852 <ul>
853 <li><uri link="http://www.alsa-project.org/">The ALSA Project</uri></li>
854 <li><uri link="http://linux-sound.org">Linux Sound/MIDI Software</uri></li>
855 </ul>
856
857 </body>
858 </section>
859 </chapter>
860 </guide>

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