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authorLinus Torvalds <torvalds@linux-foundation.org>2018-01-31 19:25:25 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2018-01-31 19:25:25 -0800
commit255442c93843f52b6891b21d0b485bf2c97f93c3 (patch)
tree8fd1daa752dbfa4721f64421ab7d4e695605d9f7 /Documentation/kbuild
parentd76e0a050e0f5e7c00e6d334f758178bbc16eb98 (diff)
parentae17a87dd7c79fa742ef5dcf06d1095eec4e1925 (diff)
Merge tag 'docs-4.16' of git://git.lwn.net/linux
Pull documentation updates from Jonathan Corbet: "Documentation updates for 4.16. New stuff includes refcount_t documentation, errseq documentation, kernel-doc support for nested structure definitions, the removal of lots of crufty kernel-doc support for unused formats, SPDX tag documentation, the beginnings of a manual for subsystem maintainers, and lots of fixes and updates. As usual, some of the changesets reach outside of Documentation/ to effect kerneldoc comment fixes. It also adds the new LICENSES directory, of which Thomas promises I do not need to be the maintainer" * tag 'docs-4.16' of git://git.lwn.net/linux: (65 commits) linux-next: docs-rst: Fix typos in kfigure.py linux-next: DOC: HWPOISON: Fix path to debugfs in hwpoison.txt Documentation: Fix misconversion of #if docs: add index entry for networking/msg_zerocopy Documentation: security/credentials.rst: explain need to sort group_list LICENSES: Add MPL-1.1 license LICENSES: Add the GPL 1.0 license LICENSES: Add Linux syscall note exception LICENSES: Add the MIT license LICENSES: Add the BSD-3-clause "Clear" license LICENSES: Add the BSD 3-clause "New" or "Revised" License LICENSES: Add the BSD 2-clause "Simplified" license LICENSES: Add the LGPL-2.1 license LICENSES: Add the LGPL 2.0 license LICENSES: Add the GPL 2.0 license Documentation: Add license-rules.rst to describe how to properly identify file licenses scripts: kernel_doc: better handle show warnings logic fs/*/Kconfig: drop links to 404-compliant http://acl.bestbits.at doc: md: Fix a file name to md-fault.c in fault-injection.txt errseq: Add to documentation tree ...
Diffstat (limited to 'Documentation/kbuild')
-rw-r--r--Documentation/kbuild/kconfig-language.txt21
1 files changed, 21 insertions, 0 deletions
diff --git a/Documentation/kbuild/kconfig-language.txt b/Documentation/kbuild/kconfig-language.txt
index c4a293a03c33..f5b9493f04ad 100644
--- a/Documentation/kbuild/kconfig-language.txt
+++ b/Documentation/kbuild/kconfig-language.txt
@@ -77,6 +77,27 @@ applicable everywhere (see syntax).
Optionally, dependencies only for this default value can be added with
"if".
+ The default value deliberately defaults to 'n' in order to avoid bloating the
+ build. With few exceptions, new config options should not change this. The
+ intent is for "make oldconfig" to add as little as possible to the config from
+ release to release.
+
+ Note:
+ Things that merit "default y/m" include:
+
+ a) A new Kconfig option for something that used to always be built
+ should be "default y".
+
+ b) A new gatekeeping Kconfig option that hides/shows other Kconfig
+ options (but does not generate any code of its own), should be
+ "default y" so people will see those other options.
+
+ c) Sub-driver behavior or similar options for a driver that is
+ "default n". This allows you to provide sane defaults.
+
+ d) Hardware or infrastructure that everybody expects, such as CONFIG_NET
+ or CONFIG_BLOCK. These are rare exceptions.
+
- type definition + default value:
"def_bool"/"def_tristate" <expr> ["if" <expr>]
This is a shorthand notation for a type definition plus a value.