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1 <?xml version='1.0' encoding="UTF-8"?>
2 <!DOCTYPE guide SYSTEM "/dtd/guide.dtd">
3
4 <!-- $Header:$ -->
5
6 <guide link="/doc/en/migration-to-2.6.xml">
7
8 <title>The complete Gentoo Linux 2.6 migration guide</title>
9
10 <author title="Author">
11 <mail link="dsd@gentoo.org">Daniel Drake</mail>
12 </author>
13 <author title="Contributor">
14 <mail link="sergey_zlodey@mail.ru">Sergey Galkin</mail>
15 </author>
16 <author title="Contributor">
17 <mail link="svyatogor@gentoo.org">Sergey Kuleshov</mail>
18 </author>
19 <author title="Editor">
20 <mail link="neysx@gentoo.org">Xavier Neys</mail>
21 </author>
22
23 <abstract>
24 This document will aid you in the process of migrating from Linux 2.4 to Linux
25 2.6, devfs to udev and OSS to ALSA.
26 </abstract>
27
28 <version>0.1.0</version>
29 <date>November 9, 2004</date>
30
31 <chapter>
32 <title>Introduction</title>
33
34 <section>
35 <title>Status of this document</title>
36 <body>
37
38 <p>
39 The migration processes described in this document are not minor changes. This
40 document is in early stages and may be missing some details but hopefully the
41 main things have been covered. If you do try a migration, please <uri
42 link="http://bugs.gentoo.org">report</uri> any problem you might encounter so
43 that we can refine this guide.
44 </p>
45
46 <p>
47 We are planning on making Linux 2.6 the default kernel for when 2005.0 is
48 released (for some arch's). At the same time, we will encourage all existing
49 users of those arch's to upgrade to Linux 2.6, as many will still be running
50 2.4. Your feedback on this document is much appreciated, so that when this
51 time comes, the document can be in good shape for the mass-migration.
52 </p>
53
54 </body>
55 </section>
56
57 <section>
58 <title>Whats new in Linux 2.6?</title>
59 <body>
60
61 <p>
62 That is no easy question to answer. Linux 2.6 is the result of over 2 years
63 of rapid development and stabilisation of new features, and is architectually
64 quite different from its 2.4 counterpart. Some of the more major changes are
65 listed below:
66 </p>
67
68 <ul>
69 <li>
70 Scheduler/Interactivity improvements: Linux feels very smooth on desktop
71 systems and copes much better than 2.4 while under load
72 </li>
73 <li>
74 Scalability: Linux now scales much better at both ends - on small embedded
75 devices and also systems with many processors
76 </li>
77 <li>Performance: Throughput from common applications is much improved</li>
78 <li>
79 Hardware support: Linux now supports many more architectures and hardware
80 devices out-of-the-box than any other operating system.
81 </li>
82 </ul>
83
84 <p>
85 Joseph Pranevich has written a very detailed document, <uri
86 link="http://www.kniggit.net/wwol26.html">The Wonderful World Of Linux
87 2.6</uri> which you may be interested to glance over. If you are interested in
88 the more technical details, you can refer to <uri
89 link="http://www.linux.org.uk/~davej/docs/post-halloween-2.6.txt">The
90 post-halloween document</uri> - but bear in mind that this is somewhat outdated
91 now.
92 </p>
93
94 </body>
95 </section>
96 <section>
97 <title>What is udev?</title>
98 <body>
99
100 <p>
101 In the past, Gentoo has instructed users to use <e>devfs</e> for managing the
102 /dev directory, which contains a series of device interfaces to allow system
103 applications to communicate with hardware (through the kernel).
104 </p>
105
106 <p>
107 <e>devfs</e>, whilst a good concept, has some internal problems, and has been
108 marked obselete in Linux 2.6.
109 </p>
110
111 <p>
112 <e>udev</e> is the new way of managing device nodes. It addresses issues with
113 previous device managers, and also attempts to solve some other problems.
114 </p>
115
116 <p>
117 The above may not mean much to you, but fear not, the hard working Gentoo
118 developers have put effort into making the migration from devfs very easy.
119 </p>
120
121 </body>
122 </section>
123 <section>
124 <title>What is ALSA?</title>
125 <body>
126
127 <p>
128 With Linux 2.4, chances are that you used OSS (open sound system) drivers to
129 power your sound card. OSS has been replaced by a newer and better set of sound
130 drivers: ALSA.
131 </p>
132
133 <p>
134 ALSA, the Advanced Linux Sound Architecture, is a new set of sound drivers with
135 a new and improved API, present in the Linux 2.6 kernel. It is backwards
136 compatible with OSS applications, provided that you select the right kernel
137 configuration options!
138 </p>
139
140 <note>
141 If you do not have any sound/audio hardware, you can safely skip over any
142 ALSA-related instructions in this document.
143 </note>
144
145 </body>
146 </section>
147 </chapter>
148
149 <chapter>
150 <title>Preparation</title>
151 <section>
152 <title>Get your system up-to-date</title>
153 <body>
154
155 <p>
156 Some of the changes brought in with Linux 2.6 also required some changes in the
157 base system applications. Before continuing, you should ensure that your system
158 is relatively up-to-date, and to be perfectly sure, you should update all world
159 and system packages where updates are available.
160 </p>
161
162 <p>
163 In particular, make sure you have the latest stable versions of the following
164 packages:
165 </p>
166
167 <ul>
168 <li><c>sys-apps/baselayout</c></li>
169 <li><c>sys-apps/util-linux</c></li>
170 <li>
171 <c>sys-kernel/genkernel</c> (only if you wish to use genkernel as opposed
172 to manual configuration)
173 </li>
174 </ul>
175
176 <pre caption="Updating all world packages">
177 # <i>emerge sync</i>
178 # <i>emerge -ua world</i>
179 </pre>
180
181 </body>
182 </section>
183 <section>
184 <title>modutils vs module-init-tools</title>
185 <body>
186
187 <p>
188 <c>sys-apps/modutils</c> is the package that provides tools such as
189 <c>modprobe</c>, <c>rmmod</c> and <c>insmod</c> for Linux 2.4.
190 </p>
191
192 <p>
193 Linux 2.6 introduces a new module format, and therefore requires new tools for
194 handling modules. These are bundled up into the
195 <c>sys-apps/module-init-tools</c> package. </p>
196
197 <p>
198 You should now remove modutils and install module-init-tools:
199 </p>
200
201 <pre caption="Switching from modutils to module-init-tools">
202 # <i>emerge unmerge modutils</i>
203 # <i>emerge module-init-tools</i>
204 </pre>
205
206 <note>
207 Don't worry - even though you have just unmerged modutils, module-init-tools
208 provides provides backwards compatibility for Linux 2.4, so you will still be
209 able to boot into Linux 2.4 and handle modules for that kernel.
210 </note>
211
212 <note>
213 For the above reason, module-init-tools might already be installed and working
214 with your existing Linux 2.4 kernel. In this case, you don't need to worry
215 about this stage - your system is already ready to deal with Linux 2.6 modules.
216 </note>
217
218 </body>
219 </section>
220 <section>
221 <title>Installing udev</title>
222 <body>
223
224 <p>
225 There is no configuration involved here. Simply use <c>emerge</c> to install
226 udev:
227 </p>
228
229 <pre caption="Installing udev">
230 # <i>emerge -a udev</i>
231 </pre>
232
233 </body>
234 </section>
235 <section>
236 <title>Installing ALSA utilities</title>
237 <body>
238
239 <p>
240 ALSA requires you to have some packages installed, so that applications can use
241 the ALSA API. These packages will also allow you to control the mixer and
242 volume levels. Install the required utilities as follows:
243 </p>
244
245 <pre caption="Installing ALSA utilities and libraries">
246 # <i>emerge -a alsa-lib alsa-utils alsa-tools alsa-headers alsa-oss</i>
247 </pre>
248
249 </body>
250 </section>
251 </chapter>
252
253 <chapter>
254 <title>Installing the Linux 2.6 sources</title>
255
256 <section>
257 <title>Choosing and installing a kernel</title>
258 <body>
259
260 <p>
261 The first thing you need to do is install sources of a 2.6 kernel of your
262 choice. The two Gentoo-supported 2.6 kernels are currently
263 <e>gentoo-dev-sources</e> (for desktops) and <e>hardened-dev-sources</e> (for
264 servers). There are others available, see the <uri
265 link="/doc/en/gentoo-kernel.xml">Gentoo Linux Kernel Guide</uri> for more
266 choices.
267 </p>
268
269 <p>
270 In this guide, we'll use <c>gentoo-dev-sources</c> as an example. Install your
271 chosen set of kernel sources using the <c>emerge</c> utility:
272 </p>
273
274 <pre caption="Installing gentoo-dev-sources">
275 # <i>emerge -a gentoo-dev-sources</i>
276 These are the packages that I would merge, in order:
277 Calculating dependencies ...done!
278 [ebuild N ] sys-kernel/gentoo-dev-sources-2.6.9-r2
279
280 Do you want me to merge these packages? [Yes/No] <i>y</i>
281 </pre>
282
283 </body>
284 </section>
285 <section>
286 <title>Updating the /usr/src/linux symbolic link</title>
287 <body>
288
289 <p>
290 Various components of the Gentoo utilities rely on /usr/src/linux being a
291 symbolic link to the kernel sources that you are running (or wish to compile
292 against).
293 </p>
294
295 <p>
296 We will now update our /usr/src/linux link to point at the kernel sources we
297 just installed. Continuing our example:
298 </p>
299
300 <pre caption="Updating the /usr/src/linux softlink">
301 # <i>cd /usr/src</i>
302 # <i>ln -sf linux-2.6.9-gentoo-r2 linux</i>
303 </pre>
304
305 </body>
306 </section>
307 </chapter>
308
309 <chapter>
310 <title>Known pitfalls with Linux 2.6 migration</title>
311 <section>
312 <body>
313
314 <p>
315 Before we get stuck into configuring the kernel, I'll attempt to detail the
316 most common errors that people make when migrating to Linux 2.6, as some of
317 these points will influence the way you configure the new kernel.
318 </p>
319
320 <note>
321 Not all of these points are relevant at this stage, but I will detail them all
322 here in one place, and you can refer back at your leisure.
323 </note>
324
325 </body>
326 </section>
327 <section>
328 <title>Don't use "make oldconfig" with a 2.4 .config</title>
329 <body>
330
331 <note>
332 If you don't understand what this means, don't worry, you won't make this
333 mistake if you follow the rest of this guide correctly.
334 </note>
335
336 <p>
337 You'll be asked many many questions, since there have been a large amount of
338 changes. Many people who do try a <c>make oldconfig</c> from a 2.4 config end
339 up creating an unworkable kernel (e.g. no output on-screen, no input from
340 keyboard, etc). Please save yourself the trouble, and use the traditional
341 <c>menuconfig</c> configuration method just this once.
342 </p>
343
344 </body>
345 </section>
346 <section>
347 <title>Don't use ide-scsi for CD/DVD writing</title>
348 <body>
349
350 <p>
351 In Linux 2.4, the only way to achieve good CD/DVD writing results was to enable
352 the (rather ugly) <c>ide-scsi</c> emulation. Thankfully, the IDE layer in Linux
353 2.6 has been extended to support CD/DVD writers much better.
354 </p>
355
356 <p>
357 You don't need to enable any extra options to support CD writing. Just be sure
358 <e>not</e> to enable <c>ide-scsi</c> as you used to.
359 </p>
360
361 </body>
362 </section>
363 <section>
364 <title>PC Speaker is now a configurable option</title>
365 <body>
366
367 <p>
368 You won't get your normal console beeps (or any response from the PC speaker at
369 all) unless you specifically enable the new PC speaker option
370 (<c>CONFIG_INPUT_PCSPKR</c>):
371 </p>
372
373 <pre caption="Location of PC speaker option">
374 Device Drivers ---&gt;
375 Input device support ---&gt;
376 [*] Misc
377 &lt;*&gt; PC Speaker support
378 </pre>
379
380 <note>
381 By "PC speaker", I am referring to the analogue speaker that beeps once when
382 your system is powering up, I am not referring to normal sound hardware used
383 for playing music, etc.
384 </note>
385
386 </body>
387 </section>
388 <section>
389 <title>New USB Storage block device driver sometimes problematic</title>
390 <body>
391
392 <p>
393 Very recently, a new USB storage device driver has been added to the kernel.
394 At the time of writing, this driver ("ub") is still in its early stages and
395 some users find it to be unreliable. If you have problems accessing your USB
396 hard disk, USB flash disk, USB card reader, or USB digital camera, then you
397 could try reverting to the older SCSI-style driver:
398 </p>
399
400 <pre caption="Disabling ub">
401 Device Drivers ---&gt;
402 Block devices ---&gt;
403 &lt; &gt; Low Performance USB Block driver
404 </pre>
405
406 <note>
407 The older SCSI-style driver (USB Mass Storage support) is enabled by default.
408 It can be found under "Device Drivers --&gt; USB support", but will generally
409 not come into effect while ub is also present.
410 </note>
411
412 </body>
413 </section>
414 <section>
415 <title>usbdevfs renamed to usbfs</title>
416 <body>
417
418 <p>
419 If you have edited your <path>/etc/fstab</path> file to customise the way that
420 the USB device filesystem gets mounted, you may have to modify the filesystem
421 type from <e>usbdevfs</e> to <e>usbfs</e>.
422 </p>
423
424 <note>
425 Recent 2.4 kernels will also allow you to use "usbfs" as well as "usbdevfs", so
426 you aren't breaking any backwards compatibility by doing this.
427 </note>
428
429 </body>
430 </section>
431 <section>
432 <title>Don't renice X</title>
433 <body>
434
435 <p>
436 If you are a desktop 2.4 user, you may have hacked your system into running X
437 at a higher priority, as in some cases it seems to provide better desktop
438 performance.
439 </p>
440
441 <p>
442 There have been many scheduler changes in 2.6 which change this behaviour. If
443 you continue to run X at a higher priority, it will do exactly what it is
444 supposed to (run the <e>display server</e> at a very high priority) and you
445 will notice consequences such as sound stuttering and slow application load
446 times because your CPU is spending too long serving X and only X.
447 </p>
448
449 <p>
450 In Linux 2.6, you no longer need to renice desktop applications to get good
451 interactivity. Please remove your "niceness" hacks!
452 </p>
453
454 </body>
455 </section>
456 <section>
457 <title>X11 config file should now use /dev/input/mice</title>
458 <body>
459
460 <p>
461 One of the changes that a default udev configuration introduces is different
462 organisation of the mouse device nodes. Previously, you would have had nodes
463 such as <path>/dev/psaux</path> and <path>/dev/mouse</path>. You will now have
464 nodes such as <path>/dev/input/mouse0</path>, <path>/dev/input/mouse1</path>,
465 and a collective <path>/dev/input/mice</path> node which combines movements
466 from all mice.
467 </p>
468
469 <p>
470 Since the old X configurations typically reference <path>/dev/mouse</path> or
471 <path>/dev/psaux</path> then you may get an error similar to the one shown
472 below when you attempt to start X11:
473 </p>
474
475 <pre caption="Common error when starting X on a udev system for the first time">
476 (EE) xf86OpenSerial: Cannot open device /dev/mouse
477 No such file or directory.
478 (EE) Mouse0: cannot open input device
479 (EE) PreInit failed for input device "Mouse0"
480 No core pointer
481 </pre>
482
483 <p>
484 To correct this, open your X11 config in a text editor, and update the mouse
485 <e>InputDevice</e> section to use the <path>/dev/input/mice</path> device. An
486 example is shown below:
487 </p>
488
489 <pre caption="Opening your X11 config file">
490 # <i>nano -w /etc/X11/xorg.conf</i>
491 </pre>
492
493 <note>
494 If you are still using XFree86, your config file will be
495 <path>/etc/X11/XF86Config</path>
496 </note>
497
498 <pre caption="Sample mouse InputDevice section">
499 Section "InputDevice"
500 Identifier "Mouse0"
501 Driver "mouse"
502 Option "Protocol" "auto"
503 Option "Device" "/dev/input/mice"
504 EndSection
505 </pre>
506
507 </body>
508 </section>
509 </chapter>
510
511 <chapter id="conf">
512 <title>Configuring, building, and installing the kernel</title>
513 <section>
514 <body>
515
516 <p>
517 As with Linux 2.4, you have two options for managing your new kernel build.
518 </p>
519
520 <ol>
521 <li>
522 The default method is to configure your kernel manually. This may seem
523 daunting but is the preferred way as long as you know your system. If you
524 wish to configure your new kernel manually, please continue on to the <uri
525 link="#manual">next chapter</uri>.
526 </li>
527 <li>
528 The alternative option is to use our <c>genkernel</c> utility to
529 automatically configure, compile, and install a kernel for you. If you wish
530 to use <c>genkernel</c> then skip over the next chapter and proceed with
531 <uri link="#genkernel">using genkernel</uri>.
532 </li>
533 </ol>
534
535 </body>
536 </section>
537 </chapter>
538
539 <chapter id="manual">
540 <title>Default: Manual configuration</title>
541 <section>
542 <title>Configuring the kernel</title>
543 <body>
544
545 <p>
546 We'll now get on with configuring the kernel. Open menuconfig in the usual way:
547 </p>
548
549 <pre caption="Invoking menuconfig">
550 # <i>cd /usr/src/linux</i>
551 # <i>make menuconfig</i>
552 </pre>
553
554 <p>
555 You will probably be familiar with using menuconfig from configuring 2.4
556 kernels. Fortunately, the front end has barely changed at all, but you will
557 observe much better organisation of kernel options, plus <e>many</e> new
558 options that weren't present in 2.4.
559 </p>
560
561 <p>
562 Be sure to enable the following important kernel options:
563 </p>
564
565 <pre caption="Required kernel options">
566 File systems ---&gt;
567 Pseudo Filesystems ---&gt;
568 [*] /proc file system support
569 [*] Virtual memory file system support (former shm fs)
570
571 <comment>(the following are required for udev):</comment>
572 General setup ---&gt;
573 [*] Support for hot-pluggable devices
574
575 Device Drivers ---&gt;
576 Block devices ---&gt;
577 &lt;*&gt; RAM disk support
578
579 <comment>(the following are required for ALSA):</comment>
580 Device Drivers ---&gt;
581 Sound ---&gt;
582 &lt;*&gt; Sound card support
583 Advanced Linux Sound Architecture ---&gt;
584 &lt;M&gt; Advanced Linux Sound Architecture
585 &lt;M&gt; Sequencer support
586 &lt;M&gt; OSS Mixer API
587 [*] OSS Sequencer API
588 <comment> (and dont forget to select your soundcard from the submenus!)</comment>
589 </pre>
590
591 <warn>
592 Previously you may have included support for the <path>/dev</path> file system
593 (now marked OBSOLETE). Do not enable devfs support. We have installed udev,
594 which we will be using instead of devfs from now on.
595 </warn>
596
597 <p>
598 Also, remember to enable support for the filesystems that you use, and the
599 hardware present in your system. Be sure to enable support for the IDE
600 controller on your motherboard if you wish to benefit from fast DMA disk
601 access. Refer to the <uri
602 link="/doc/en/handbook/handbook-x86.xml?part=1&amp;chap=7">Configuring the
603 Kernel</uri> section of the <uri link="/doc/en/handbook/index.xml">Gentoo
604 Handbook</uri> for additional guidance here.
605 </p>
606
607 </body>
608 </section>
609 <section>
610 <title>Building the kernel</title>
611 <body>
612
613 <p>
614 Now that we have configured the kernel, we can start the compilation process:
615 </p>
616
617 <pre caption="Compiling the kernel source">
618 # <i>make &amp;&amp; make modules_install</i>
619 </pre>
620
621 <note>
622 You may recall having to run <c>make dep</c> with Linux 2.4 sources. This is no
623 longer required.
624 </note>
625
626 <p>
627 Wait for the kernel compilation to complete (and observe the much more readable
628 compilation output).
629 </p>
630
631 </body>
632 </section>
633 <section>
634 <title>Installing the kernel</title>
635 <body>
636
637 <p>
638 The next step is mounting your <path>/boot</path> partition and copying the
639 kernel image over. You must then update your bootloader config manually.
640 </p>
641
642 <pre caption="Installing the kernel">
643 # <i>mount /boot</i>
644 # <i>cp arch/i386/boot/bzImage /boot/bzImage-2.6.9-gentoo-r2</i>
645 # <i>cp System.map /boot/System.map-2.6.9-gentoo-r2</i>
646 </pre>
647
648 <p>
649 Note that the above instructions are examples only, you should follow your
650 usual procedure of updating kernels by following the instructions in the <uri
651 link="/doc/en/handbook/index.xml">Gentoo Handbook</uri> (see the <uri
652 link="/doc/en/handbook/handbook-x86.xml?part=1&amp;chap=7">Configuring the
653 Kernel</uri> chapter).
654 </p>
655
656 <p>
657 When updating your bootloader config, do not remove the old entry pointing at
658 your 2.4 kernel. This way, you will easily be able to switch between the two if
659 something is not working.
660 </p>
661
662 <p>
663 Now continue onto the <uri link="#modules">Module Configuration</uri> section.
664 </p>
665
666 </body>
667 </section>
668 </chapter>
669
670 <chapter id="genkernel">
671 <title>Alternative: Using genkernel</title>
672 <section>
673 <body>
674
675 <p>
676 If you prefer to use genkernel instead of manually configuring your kernel, you
677 will be happy to hear that using genkernel to produce 2.6 kernels is very
678 similar to the process you performed when producing your previous 2.4 kernel.
679 </p>
680
681 <p>
682 You should invoke genkernel as shown below:
683 </p>
684
685 <pre caption="Invoking genkernel with some common arguments">
686 # <i>genkernel --udev --menuconfig --bootloader=grub all</i>
687 </pre>
688
689 <p>
690 In the above example, we also take advantage of genkernel features to open
691 menuconfig to allow you to customise the kernel configuration (if you wish),
692 and to update the grub bootloader configuration after compilation.
693 </p>
694
695 <p>
696 You should choose genkernel arguments that suit you, but do not forget to
697 include the <c>--udev</c> argument! Refer to the <uri
698 link="/doc/en/genkernel.xml">Gentoo Linux Genkernel Guide</uri> and the <uri
699 link="/doc/en/handbook/handbook-x86.xml?part=1&amp;chap=7">Configuring the
700 Kernel</uri> chapter of the <uri link="/doc/en/handbook/index.xml">Gentoo
701 Handbook</uri> for additional information.
702 </p>
703
704 </body>
705 </section>
706 </chapter>
707
708 <chapter id="modules">
709 <title>Module Configuration</title>
710
711 <section>
712 <title>Installing external modules</title>
713 <body>
714
715 <p>
716 Many users will additionally rely on kernel modules that are built outside of
717 the kernel tree. Common examples are the binary ATI and Nvidia graphics
718 drivers. You now need to install those modules, which will compile against the
719 2.6 sources found at <path>/usr/src/linux</path>. This is the usual case of
720 <c>emerge packagename</c> for all the external modules you are used to using
721 with 2.4.
722 </p>
723
724 <p>
725 Refer again to the <uri
726 link="/doc/en/handbook/handbook-x86.xml?part=1&amp;chap=7">Configuring the
727 Kernel</uri> chapter of the <uri link="/doc/en/handbook/index.xml">Gentoo
728 Handbook</uri> for more info.
729 </p>
730
731 </body>
732 </section>
733 <section>
734 <title>Autoloading modules</title>
735 <body>
736
737 <p>
738 You may have decided to compile some kernel components as modules (as opposed
739 to compiled directly into the kernel) and would like to have them autoloaded on
740 bootup like you did with 2.4. Also, if you installed any external modules from
741 the portage tree (as described above) you will probably want to autoload them
742 too.
743 </p>
744
745 <p>
746 You can achieve this similarly as to how you did with 2.4. Simply open up the
747 file <path>/etc/modules.autoload.d/kernel-2.6</path> in a text editor and list
748 the names of the modules you would like autoloaded.
749 </p>
750
751 <pre caption="Opening the module autoload list in nano">
752 # <i>nano -w /etc/modules.autoload.d/kernel-2.6</i>
753 </pre>
754
755 <pre caption="Sample autoload list to load the 3c59x and nvidia modules">
756 # /etc/modules.autoload.d/kernel-2.6: kernel modules to load when system boots.
757 #
758 # Note that this file is for 2.6 kernels.
759 #
760 # Add the names of modules that you'd like to load when the system
761 # starts into this file, one per line. Comments begin with # and
762 # are ignored. Read man modules.autoload for additional details.
763
764 3c59x
765 nvidia
766 </pre>
767
768 </body>
769 </section>
770 <section>
771 <title>Configuring the ALSA modules</title>
772 <body>
773
774 <p>
775 You will have noticed that we chose to compile ALSA as modules. We can now
776 configure ALSA's behaviour easily. However, we also need to configure which
777 modules are to be loaded. Open up <path>/etc/modules.d/alsa</path> in your text
778 editor:
779 </p>
780
781 <pre caption="Opening /etc/modules.d/alsa in nano">
782 # <i>nano -w /etc/modules.d/alsa</i>
783 </pre>
784
785 <p>
786 Now look for the section marked as <e>IMPORTANT</e>. In most cases, you just
787 need to uncomment and modify the snd-card-0 and snd-slot-0 aliases.
788 </p>
789
790 <pre caption="Sample section of /etc/modules.d/alsa">
791 ## IMPORTANT:
792 ## You need to customise this section for your specific sound card(s)
793 ## and then run `update-modules' command.
794 ## Read alsa-driver's INSTALL file in /usr/share/doc for more info.
795 ##
796 ## ALSA portion
797
798 # My laptop uses the snd-maestro3 driver
799 alias snd-card-0 snd-maestro3
800
801 ## OSS/Free portion
802
803 # Generally all you need to do is uncomment this line:
804 alias sound-slot-0 snd-card-0
805 </pre>
806
807 <p>
808 For more info on which driver name to use, consult the <uri
809 link="/doc/en/alsa-guide.xml">Gentoo Linux ALSA Guide</uri>. Remember to prefix
810 it with <e>snd-</e> in this file.
811 </p>
812
813 <p>
814 Finally, set the <c>alsasound</c> init script to be executed on bootup:
815 </p>
816
817 <pre caption="Adding alsasound to default runlevel">
818 # <i>rc-update add alsasound boot</i>
819 </pre>
820
821 </body>
822 </section>
823 </chapter>
824
825 <chapter>
826 <title>Booting into Linux 2.6</title>
827 <section>
828 <body>
829
830 <p>
831 It's now time to boot into Linux 2.6. Close all applications and reboot:
832 </p>
833
834 <pre caption="Rebooting">
835 # <i>modules-update</i>
836 # <i>umount /boot</i>
837 # <i>reboot</i>
838 </pre>
839
840 <p>
841 When you reboot, if you followed this document correctly so far, you will have
842 the option of either loading Linux 2.4 or Linux 2.6 from your bootloader.
843 Choose Linux 2.6.
844 </p>
845
846 <p>
847 Once the system has booted, check that things are working. If you made a
848 mistake in the kernel configuration, don't worry, you can skip back to the
849 <uri link="#conf">Configuring, building, and installing the kernel</uri>
850 section, make your change, recompile and install new kernel image, reboot, and
851 try again!
852 </p>
853
854 </body>
855 </section>
856 <section>
857 <title>Unmuting ALSA channels</title>
858 <body>
859
860 <p>
861 By default, ALSA channels are muted, so you won't hear anything when you go to
862 play a sound. You need to unmute them now. Run the <c>alsamixer</c> program
863 from a console and use the arrow keys to move around and adjust volumes, and
864 the M key to mute and unmute. Read the <uri
865 link="/doc/en/alsa-guide.xml">Gentoo Linux ALSA Guide</uri> for more complete
866 documentation and other ways to do this.
867 </p>
868
869 <note>
870 The alsasound init script that we put in the default runlevel will save mixer
871 levels on shutdown and restore them on bootup. You won't need to set all these
872 volumes every time you boot!
873 </note>
874
875 </body>
876 </section>
877 </chapter>
878
879 <chapter>
880 <title>Header files and NPTL</title>
881 <section>
882 <body>
883
884 <p>
885 By now you are running Linux 2.6 and hopefully have all issues ironed out. You
886 should now update your Linux kernel header files and re-merge glibc so that
887 userspace applications can take advantage of new Linux 2.6 features.
888 </p>
889
890 <pre caption="Updating to linux26-headers">
891 # <i>emerge linux26-headers</i>
892 # <i>emerge unmerge linux-headers</i>
893 </pre>
894
895 <p>
896 After updating your headers package, you should generally re-merge glibc.
897 There is a new feature here that you may be interested in - NPTL. NPTL is a new
898 threading model present in Linux 2.6, which features much quicker thread create
899 and destroy times. This won't make much of a difference to most systems, but
900 you may wish to enable it during this migration process! To enable NPTL, edit
901 <path>/etc/make.conf</path>, adding <e>nptl</e> to your USE variable.
902 </p>
903
904 <warn>
905 With the current stable glibc ebuilds, you will be unable to boot a 2.4 kernel
906 after compiling glibc with USE="nptl". Be warned, be careful!
907 </warn>
908
909 <p>
910 Now re-merge glibc (you should do this even if you did not choose to enable
911 NPTL).
912 </p>
913
914 <pre caption="Reinstalling glibc against the new kernel headers">
915 # <i>emerge -a glibc</i>
916 </pre>
917
918 <p>
919 If you enabled NPTL, existing binaries will not use it until they are
920 recompiled. However, any binaries compiled from this point onwards <e>will</e>
921 use NPTL. You may wish to recompile all binaries now, e.g.:
922 </p>
923
924 <pre caption="Recompiling all packages on the system">
925 # <i>emerge -e world</i>
926 </pre>
927
928 <p>
929 Alternatively, you can just let your system "naturally" convert itself to NPTL
930 as you update to newer versions of packages when they are released.
931 </p>
932
933 </body>
934 </section>
935 </chapter>
936
937 <chapter>
938 <title>Closing remarks</title>
939 <section>
940 <title>Problems?</title>
941 <body>
942
943 <p>
944 With the incredible amount of work that went into Linux 2.6, it is sometimes
945 inevitable that things which used to work fine, no longer function as expected.
946 </p>
947
948 <p>
949 If you have any problems with your 2.6 kernel, and you can confirm that this
950 problem does not exist with Linux 2.4, then please open a bug with us on our
951 <uri link="http://bugs.gentoo.org">Bugzilla</uri>. We will investigate the
952 issue, and if we find that it is a problem in the mainline kernel, we may then
953 ask you to file a report at the central kernel bugzilla.
954 </p>
955
956 </body>
957 </section>
958 <section>
959 <title>Conclusion</title>
960 <body>
961
962 <p>
963 Hopefully you have just completed a smooth migration and you are enjoying the
964 benefits which Linux 2.6 brings over 2.4. As I mentioned at the start, we are
965 looking for feedback on this document - even if your migration went perfectly
966 smoothly. Please <mail link="dsd@gentoo.org">mail me</mail> your feedback so
967 that we can get this document in perfect shape for when 2005.0 comes around.
968 Thanks!
969 </p>
970
971 </body>
972 </section>
973 </chapter>
974 </guide>

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