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42 <h1>Mini-DebConf Paris 2012</h1>
43 <h2>The Linux kernel in Debian</h2>
48 <div class="presentation">
51 <h1>The Linux kernel in Debian</h1>
52 <object data="tux-debian.svg" width="35%" align="right"></object>
53 <h3>Ben Hutchings and Max Attems</h3>
57 <h1>Ben Hutchings</h1>
60 Professional software developer since 1998
63 Debian contributor since 2003
66 Regular Linux contributor since 2008
69 Maintaining a net driver in my day job, plus core networking
70 and PCI code as necessary
75 Debian kernel contributor since 2008; uploader since 2009
78 Initially trying to deal with the non-free firmware issue
81 Moved on to triaging bugs, fixing bugs, backporting
82 features, updating packaging...
98 <ul class="incremental">
100 Started by Linus Torvalds in 1991 as a kernel for i386
101 PCs: <q>just a hobby, won't be big and professional like gnu</q>
104 Adopted as the kernel of the Debian system in 1993
107 After 20 years' development, supports more hardware
108 architectures and devices than anything else
109 <ul class="incremental">
111 Hardware vendors <em>must</em> provide Linux drivers because
112 their customers demand it
117 Still the default kernel for the Debian system
123 <h1>Linux release model</h1>
127 <ul class="incremental">
129 Development results in a new stable(-ish) release every 2-3
131 <ul class="incremental">
133 git (and previously BitKeeper) made distributed development
134 and testing a lot easier
139 Each 2.6.<var>x</var> and 3.<var>x</var> release has a stable
140 update branch; releases numbered 2.6.<var>x</var>.<var>y</var>
141 and 3.<var>x</var>.<var>y</var>
142 <ul class="incremental">
144 Usually closed shortly after next stable release, but may
145 continue as a 'longterm' branch (e.g. 2.6.32.<var>y</var>)
153 <h1>Debian kernel team (1)</h1>
157 <ul class="incremental">
159 Currently 5 general maintainers: Maximilian Attems, Bastian
160 Blank, dann frazier, Ben Hutchings, Moritz Muehlenhoff
163 Many more specialised contributors:
165 <li>Specific architectures</li>
166 <li>Specific features (e.g. Xen)</li>
171 Would appreciate more help, particularly with bug triage and
178 <h1>Debian kernel team (2)</h1>
182 <ul class="incremental">
184 Bug triage - takes a huge amount of time
187 Backport bug fixes and features - particularly new hardware
189 <ul class="incremental">
190 <li>...while trying not to change kernel ABI in stable</li>
194 Update build configurations for each new upstream release -
195 e.g. to enable new drivers
198 Try to ensure smooth upgrades when there are major
199 implementation changes - e.g. KMS, switch to libata drivers
202 Integrate <em>some</em> features not accepted upstream
208 <h1>Official Linux kernel packages (1)</h1>
210 Main source package is <span class="package">linux</span>. Most
211 binary package names change regularly.
213 <ul class="incremental">
215 <span class="package">linux-image-<var>upstream</var>-<var>abi</var>-<var>flavour</var></span>
216 - compiled kernel and modules
219 <span class="package">linux-headers-<var>upstream</var>-<var>abi</var>-<var>flavour</var></span>
220 (and others) - development package for OOT modules
223 <span class="package">linux-libc-dev</span> - headers for userland
226 <span class="package">linux-source-<var>upstream</var></span> -
230 <span class="package">linux-doc-<var>upstream</var></span>,
231 <span class="package">linux-manual-<var>upstream</var></span>, etc.
234 <span class="package">linux-support-<var>upstream</var>-<var>abi</var></span> -
235 scripts and metadata to support linux-latest
241 <h1>Official Linux kernel packages (2)</h1>
243 The <span class="package">linux-latest</span> source package builds meta-packages
244 to support automatic upgrades between binaries built
245 from <span class="package">linux</span>.
247 <ul class="incremental">
249 <span class="package">linux-image-<var>flavour</var></span>
252 <span class="package">linux-headers-<var>flavour</var></span>
255 <span class="package">linux-source</span>,
256 <span class="package">linux-doc</span>,
257 <span class="package">linux-tools</span>, etc.
260 <p class="incremental">
261 The installer will normally install
262 <span class="package">linux-image-<var>flavour</var></span> (for
263 some appropriate <var>flavour</var>).
268 <h1>Official Linux kernel packages (3)</h1>
269 <ul class="incremental">
271 <span class="package">firmware-free</span> - separate 'firmware'
275 <span class="package">linux-base</span> - base package for
279 <span class="package">linux-tools</span> builds
282 <span class="package">linux-kbuild-<var>upstream</var></span> -
283 kernel build system and tools for building OOT modules
286 <span class="package">linux-tools-<var>upstream</var></span>
290 <span class="package">usbip</span> - usbip configuration
299 <h1>Custom Linux kernel builds</h1>
301 The official packages work for most users, but not all:
303 <ul class="incremental">
305 Different ARM platforms need incompatible configurations,
306 and we cannot build them all
309 New features are not enabled immediately if we are worried
310 about potential regressions
313 <p class="incremental">
314 Using either upstream source or Debian linux-source package:
316 <ul class="incremental">
318 <span class="package">make && make install</span>
321 <span class="package">make deb-pkg</span> - build packages
324 <span class="package">make-kpkg</span> - build packages with
325 more customisation; requires
326 <span class="package">kernel-package</span>
332 <h1>Extra features</h1>
334 Always aim to get patches merged upstream. But many big features
335 that users want added are <em>not</em> merged upstream for a long
336 time. Kernel team expects features to be upstream first, then
339 <p class="incremental">
340 But there have been exceptions:
342 <ul class="incremental">
344 OpenVZ and VServer - being reimplemented upstream with cgroups
351 aufs - needed for Debian Live
354 PREEMPT_RT - gradually being merged upstream; new option in
355 amd64 and i386 packages
361 <h1>Out-of-tree modules</h1>
363 The kernel team does not encourage the use of out-of-tree modules.
364 However, we support them by providing development packages and by
365 avoiding ABI changes during a stable release.
367 <p class="incremental">
368 Debian has two packages to aid in building out-of-tree modules:
370 <ul class="incremental">
372 <span class="package">dkms</span> - builds and installs modules
373 automatically. Can build packages for installation on other
374 systems. Also supported by Ubuntu and SUSE.
377 <span class="package">module-assistant</span> - builds packages
378 as directed. Uses a separate package name for each kernel ABI.
384 <h1>Firmware files</h1>
385 <ul class="incremental">
387 Most peripherals have microcontroller running non-free
388 firmware; some require host to load it
391 Several drivers used to include firmware, making kernel
392 non-free. Fudged with GRs for a while; finally fixed in squeeze
395 Users with these devices - almost any wifi card, some network
396 controllers and Radeon GPUs - will still need the firmware
400 Kernel team maintains
401 <span class="package">firmware-nonfree</span> source package
402 covering most firmware files that are clearly redistributable
405 Also collected in linux-firmware.git repository maintained by
406 David Woodhouse and Ben Hutchings
412 <h1>Documentation</h1>
413 <ul class="incremental">
415 <span class="package">manpages-dev</span> - the system call API
418 <span class="package">linux-doc-</span><var>upstream</var> -
419 miscellaneous upstream documentation
422 <span class="package">linux-manual-</span><var>upstream</var> -
423 the internal API, based on structured comments
426 <span class="package">debian-kernel-handbook</span> -
427 Debian-specific information; currently also Linux-specific but
428 could cover other kernels
431 <a href="http://wiki.debian.org/DebianKernel">http://wiki.debian.org/DebianKernel</a>
445 Linux 'Tux' logo © Larry Ewing, Simon Budig.
447 Redistribution is free but has to include this notice.
450 <li>Modified by Ben to add Debian open-ND logo</li>
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