1=================================
2Configuration targets and editors
3=================================
4
5This file contains some assistance for using ``make *config``.
6
7Use ``make help`` to list all of the possible configuration targets.
8
9The xconfig ('qconf'), menuconfig ('mconf'), and nconfig ('nconf')
10programs also have embedded help text.  Be sure to check that for
11navigation, search, and other general help text.
12
13The gconfig ('gconf') program has limited help text.
14
15
16General
17=======
18
19New kernel releases often introduce new config symbols.  Often more
20important, new kernel releases may rename config symbols.  When
21this happens, using a previously working .config file and running
22"make oldconfig" won't necessarily produce a working new kernel
23for you, so you may find that you need to see what NEW kernel
24symbols have been introduced.
25
26To see a list of new config symbols, use::
27
28    cp user/some/old.config .config
29    make listnewconfig
30
31and the config program will list any new symbols, one per line.
32
33Alternatively, you can use the brute force method::
34
35    make oldconfig
36    scripts/diffconfig .config.old .config | less
37
38
39Environment variables
40=====================
41
42Environment variables for ``*config``:
43
44``KCONFIG_CONFIG``
45    This environment variable can be used to specify a default kernel config
46    file name to override the default name of ".config".
47
48``KCONFIG_DEFCONFIG_LIST``
49    This environment variable specifies a list of config files which can be
50    used as a base configuration in case the .config does not exist yet.
51    Entries in the list are separated with whitespaces to each other, and
52    the first one that exists is used.
53
54``KCONFIG_OVERWRITECONFIG``
55    If you set KCONFIG_OVERWRITECONFIG in the environment, Kconfig will not
56    break symlinks when .config is a symlink to somewhere else.
57
58``KCONFIG_WARN_UNKNOWN_SYMBOLS``
59    This environment variable makes Kconfig warn about all unrecognized
60    symbols in the config input.
61
62``KCONFIG_WERROR``
63    If set, Kconfig treats warnings as errors.
64
65``CONFIG_``
66    If you set ``CONFIG_`` in the environment, Kconfig will prefix all symbols
67    with its value when saving the configuration, instead of using the
68    default, ``CONFIG_``.
69
70Environment variables for ``{allyes/allmod/allno/rand}config``:
71
72``KCONFIG_ALLCONFIG``
73    The allyesconfig/allmodconfig/allnoconfig/randconfig variants can also
74    use the environment variable KCONFIG_ALLCONFIG as a flag or a filename
75    that contains config symbols that the user requires to be set to a
76    specific value.  If KCONFIG_ALLCONFIG is used without a filename where
77    KCONFIG_ALLCONFIG == "" or KCONFIG_ALLCONFIG == "1", ``make *config``
78    checks for a file named "all{yes/mod/no/def/random}.config"
79    (corresponding to the ``*config`` command that was used) for symbol values
80    that are to be forced.  If this file is not found, it checks for a
81    file named "all.config" to contain forced values.
82
83    This enables you to create "miniature" config (miniconfig) or custom
84    config files containing just the config symbols that you are interested
85    in.  Then the kernel config system generates the full .config file,
86    including symbols of your miniconfig file.
87
88    This ``KCONFIG_ALLCONFIG`` file is a config file which contains
89    (usually a subset of all) preset config symbols.  These variable
90    settings are still subject to normal dependency checks.
91
92    Examples::
93
94        KCONFIG_ALLCONFIG=custom-notebook.config make allnoconfig
95
96    or::
97
98        KCONFIG_ALLCONFIG=mini.config make allnoconfig
99
100    or::
101
102        make KCONFIG_ALLCONFIG=mini.config allnoconfig
103
104    These examples will disable most options (allnoconfig) but enable or
105    disable the options that are explicitly listed in the specified
106    mini-config files.
107
108Environment variables for ``randconfig``:
109
110``KCONFIG_SEED``
111    You can set this to the integer value used to seed the RNG, if you want
112    to somehow debug the behaviour of the kconfig parser/frontends.
113    If not set, the current time will be used.
114
115``KCONFIG_PROBABILITY``
116    This variable can be used to skew the probabilities. This variable can
117    be unset or empty, or set to three different formats:
118
119    =======================     ==================  =====================
120    KCONFIG_PROBABILITY         y:n split           y:m:n split
121    =======================     ==================  =====================
122    unset or empty              50  : 50            33  : 33  : 34
123    N                            N  : 100-N         N/2 : N/2 : 100-N
124    [1] N:M                     N+M : 100-(N+M)      N  :  M  : 100-(N+M)
125    [2] N:M:L                    N  : 100-N          M  :  L  : 100-(M+L)
126    =======================     ==================  =====================
127
128where N, M and L are integers (in base 10) in the range [0,100], and so
129that:
130
131    [1] N+M is in the range [0,100]
132
133    [2] M+L is in the range [0,100]
134
135Examples::
136
137    KCONFIG_PROBABILITY=10
138        10% of booleans will be set to 'y', 90% to 'n'
139        5% of tristates will be set to 'y', 5% to 'm', 90% to 'n'
140    KCONFIG_PROBABILITY=15:25
141        40% of booleans will be set to 'y', 60% to 'n'
142        15% of tristates will be set to 'y', 25% to 'm', 60% to 'n'
143    KCONFIG_PROBABILITY=10:15:15
144        10% of booleans will be set to 'y', 90% to 'n'
145        15% of tristates will be set to 'y', 15% to 'm', 70% to 'n'
146
147Environment variables for ``syncconfig``:
148
149``KCONFIG_NOSILENTUPDATE``
150    If this variable has a non-blank value, it prevents silent kernel
151    config updates (requires explicit updates).
152
153``KCONFIG_AUTOCONFIG``
154    This environment variable can be set to specify the path & name of the
155    "auto.conf" file.  Its default value is "include/config/auto.conf".
156
157``KCONFIG_AUTOHEADER``
158    This environment variable can be set to specify the path & name of the
159    "autoconf.h" (header) file.
160    Its default value is "include/generated/autoconf.h".
161
162
163menuconfig
164==========
165
166Searching in menuconfig:
167
168    The Search function searches for kernel configuration symbol
169    names, so you have to know something close to what you are
170    looking for.
171
172    Example::
173
174        /hotplug
175        This lists all config symbols that contain "hotplug",
176        e.g., HOTPLUG_CPU, MEMORY_HOTPLUG.
177
178    For search help, enter / followed by TAB-TAB (to highlight
179    <Help>) and Enter.  This will tell you that you can also use
180    regular expressions (regexes) in the search string, so if you
181    are not interested in MEMORY_HOTPLUG, you could try::
182
183        /^hotplug
184
185    When searching, symbols are sorted thus:
186
187    - first, exact matches, sorted alphabetically (an exact match
188      is when the search matches the complete symbol name);
189    - then, other matches, sorted alphabetically.
190
191    For example, ^ATH.K matches:
192
193        ATH5K ATH9K ATH5K_AHB ATH5K_DEBUG [...] ATH6KL ATH6KL_DEBUG
194        [...] ATH9K_AHB ATH9K_BTCOEX_SUPPORT ATH9K_COMMON [...]
195
196    of which only ATH5K and ATH9K match exactly and so are sorted
197    first (and in alphabetical order), then come all other symbols,
198    sorted in alphabetical order.
199
200    In this menu, pressing the key in the (#) prefix will jump
201    directly to that location. You will be returned to the current
202    search results after exiting this new menu.
203
204User interface options for 'menuconfig':
205
206``MENUCONFIG_COLOR``
207    It is possible to select different color themes using the variable
208    MENUCONFIG_COLOR.  To select a theme use::
209
210        make MENUCONFIG_COLOR=<theme> menuconfig
211
212    Available themes are::
213
214      - mono       => selects colors suitable for monochrome displays
215      - blackbg    => selects a color scheme with black background
216      - classic    => theme with blue background. The classic look
217      - bluetitle  => a LCD friendly version of classic. (default)
218
219``MENUCONFIG_MODE``
220    This mode shows all sub-menus in one large tree.
221
222    Example::
223
224        make MENUCONFIG_MODE=single_menu menuconfig
225
226
227nconfig
228=======
229
230nconfig is an alternate text-based configurator.  It lists function
231keys across the bottom of the terminal (window) that execute commands.
232You can also just use the corresponding numeric key to execute the
233commands unless you are in a data entry window.  E.g., instead of F6
234for Save, you can just press 6.
235
236Use F1 for Global help or F3 for the Short help menu.
237
238Searching in nconfig:
239
240    You can search either in the menu entry "prompt" strings
241    or in the configuration symbols.
242
243    Use / to begin a search through the menu entries.  This does
244    not support regular expressions.  Use <Down> or <Up> for
245    Next hit and Previous hit, respectively.  Use <Esc> to
246    terminate the search mode.
247
248    F8 (SymSearch) searches the configuration symbols for the
249    given string or regular expression (regex).
250
251    In the SymSearch, pressing the key in the (#) prefix will
252    jump directly to that location. You will be returned to the
253    current search results after exiting this new menu.
254
255Environment variables:
256
257``NCONFIG_MODE``
258    This mode shows all sub-menus in one large tree.
259
260    Example::
261
262        make NCONFIG_MODE=single_menu nconfig
263
264
265xconfig
266=======
267
268Searching in xconfig:
269
270    The Search function searches for kernel configuration symbol
271    names, so you have to know something close to what you are
272    looking for.
273
274    Example::
275
276        Ctrl-F hotplug
277
278    or::
279
280        Menu: File, Search, hotplug
281
282    lists all config symbol entries that contain "hotplug" in
283    the symbol name.  In this Search dialog, you may change the
284    config setting for any of the entries that are not grayed out.
285    You can also enter a different search string without having
286    to return to the main menu.
287
288
289gconfig
290=======
291
292Searching in gconfig:
293
294    There is no search command in gconfig.  However, gconfig does
295    have several different viewing choices, modes, and options.
296