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authorRandy Dunlap <randy.dunlap@oracle.com>2008-02-29 17:21:53 -0500
committerSam Ravnborg <sam@ravnborg.org>2009-01-02 14:43:25 -0500
commit2af238e455ef5fd31c2f7a06c2db3f13d843b9bf (patch)
tree9a1da45a4b81a03f25742a57843228362ca66fc5 /Documentation/kbuild/kconfig.txt
parent80a7d1d991e35b0370c0396f36f6a076869a6bac (diff)
kbuild: make *config usage docs
Create a kconfig user assistance guide, with a few tips and hints about using menuconfig, xconfig, and gconfig. Mostly contains user interface, environment variables, and search topics, along with mini.config/custom.config usage. Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
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1This file contains some assistance for using "make *config".
2
3Use "make help" to list all of the possible configuration targets.
4
5The xconfig ('qconf') and menuconfig ('mconf') programs also
6have embedded help text. Be sure to check it for navigation,
7search, and other general help text.
8
9======================================================================
10General
11--------------------------------------------------
12
13New kernel releases often introduce new config symbols. Often more
14important, new kernel releases may rename config symbols. When
15this happens, using a previously working .config file and running
16"make oldconfig" won't necessarily produce a working new kernel
17for you, so you may find that you need to see what NEW kernel
18symbols have been introduced.
19
20To see a list of new config symbols when using "make oldconfig", use
21
22 cp user/some/old.config .config
23 yes "" | make oldconfig >conf.new
24
25and the config program will list as (NEW) any new symbols that have
26unknown values. Of course, the .config file is also updated with
27new (default) values, so you can use:
28
29 grep "(NEW)" conf.new
30
31to see the new config symbols or you can 'diff' the previous and
32new .config files to see the differences:
33
34 diff .config.old .config | less
35
36(Yes, we need something better here.)
37
38
39======================================================================
40menuconfig
41--------------------------------------------------
42
43SEARCHING for CONFIG symbols
44
45Searching in menuconfig:
46
47 The Search function searches for kernel configuration symbol
48 names, so you have to know something close to what you are
49 looking for.
50
51 Example:
52 /hotplug
53 This lists all config symbols that contain "hotplug",
54 e.g., HOTPLUG, HOTPLUG_CPU, MEMORY_HOTPLUG.
55
56 For search help, enter / followed TAB-TAB-TAB (to highlight
57 <Help>) and Enter. This will tell you that you can also use
58 regular expressions (regexes) in the search string, so if you
59 are not interested in MEMORY_HOTPLUG, you could try
60
61 /^hotplug
62
63
64______________________________________________________________________
65Color Themes for 'menuconfig'
66
67It is possible to select different color themes using the variable
68MENUCONFIG_COLOR. To select a theme use:
69
70 make MENUCONFIG_COLOR=<theme> menuconfig
71
72Available themes are:
73 mono => selects colors suitable for monochrome displays
74 blackbg => selects a color scheme with black background
75 classic => theme with blue background. The classic look
76 bluetitle => a LCD friendly version of classic. (default)
77
78______________________________________________________________________
79Environment variables in 'menuconfig'
80
81KCONFIG_ALLCONFIG
82--------------------------------------------------
83(partially based on lkml email from/by Rob Landley, re: miniconfig)
84--------------------------------------------------
85The allyesconfig/allmodconfig/allnoconfig/randconfig variants can
86also use the environment variable KCONFIG_ALLCONFIG as a flag or a
87filename that contains config symbols that the user requires to be
88set to a specific value. If KCONFIG_ALLCONFIG is used without a
89filename, "make *config" checks for a file named
90"all{yes/mod/no/random}.config" (corresponding to the *config command
91that was used) for symbol values that are to be forced. If this file
92is not found, it checks for a file named "all.config" to contain forced
93values.
94
95This enables you to create "miniature" config (miniconfig) or custom
96config files containing just the config symbols that you are interested
97in. Then the kernel config system generates the full .config file,
98including dependencies of your miniconfig file, based on the miniconfig
99file.
100
101This 'KCONFIG_ALLCONFIG' file is a config file which contains
102(usually a subset of all) preset config symbols. These variable
103settings are still subject to normal dependency checks.
104
105Examples:
106 KCONFIG_ALLCONFIG=custom-notebook.config make allnoconfig
107or
108 KCONFIG_ALLCONFIG=mini.config make allnoconfig
109or
110 make KCONFIG_ALLCONFIG=mini.config allnoconfig
111
112These examples will disable most options (allnoconfig) but enable or
113disable the options that are explicitly listed in the specified
114mini-config files.
115
116KCONFIG_NOSILENTUPDATE
117--------------------------------------------------
118If this variable has a non-blank value, it prevents silent kernel
119config udpates (requires explicit updates).
120
121KCONFIG_CONFIG
122--------------------------------------------------
123This environment variable can be used to specify a default kernel config
124file name to override the default name of ".config".
125
126KCONFIG_OVERWRITECONFIG
127--------------------------------------------------
128If you set KCONFIG_OVERWRITECONFIG in the environment, Kconfig will not
129break symlinks when .config is a symlink to somewhere else.
130
131KCONFIG_NOTIMESTAMP
132--------------------------------------------------
133If this environment variable exists and is non-null, the timestamp line
134in generated .config files is omitted.
135
136KCONFIG_AUTOCONFIG
137--------------------------------------------------
138This environment variable can be set to specify the path & name of the
139"auto.conf" file. Its default value is "include/config/auto.conf".
140
141KCONFIG_AUTOHEADER
142--------------------------------------------------
143This environment variable can be set to specify the path & name of the
144"autoconf.h" (header) file. Its default value is "include/linux/autoconf.h".
145
146______________________________________________________________________
147menuconfig User Interface Options
148----------------------------------------------------------------------
149MENUCONFIG_MODE
150--------------------------------------------------
151This mode shows all sub-menus in one large tree.
152
153Example:
154 MENUCONFIG_MODE=single_menu make menuconfig
155
156======================================================================
157xconfig
158--------------------------------------------------
159
160Searching in xconfig:
161
162 The Search function searches for kernel configuration symbol
163 names, so you have to know something close to what you are
164 looking for.
165
166 Example:
167 Ctrl-F hotplug
168 or
169 Menu: File, Search, hotplug
170
171 lists all config symbol entries that contain "hotplug" in
172 the symbol name. In this Search dialog, you may change the
173 config setting for any of the entries that are not grayed out.
174 You can also enter a different search string without having
175 to return to the main menu.
176
177
178======================================================================
179gconfig
180--------------------------------------------------
181
182Searching in gconfig:
183
184 None (gconfig isn't maintained as well as xconfig or menuconfig);
185 however, gconfig does have a few more viewing choices than
186 xconfig does.
187
188###