1===================
2Kconfig make config
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
13General
14-------
15
16New kernel releases often introduce new config symbols.  Often more
17important, new kernel releases may rename config symbols.  When
18this happens, using a previously working .config file and running
19"make oldconfig" won't necessarily produce a working new kernel
20for you, so you may find that you need to see what NEW kernel
21symbols have been introduced.
22
23To see a list of new config symbols, use::
24
25	cp user/some/old.config .config
26	make listnewconfig
27
28and the config program will list any new symbols, one per line.
29
30Alternatively, you can use the brute force method::
31
32	make oldconfig
33	scripts/diffconfig .config.old .config | less
34
35----------------------------------------------------------------------
36
37Environment variables for `*config`
38
39KCONFIG_CONFIG
40--------------
41This environment variable can be used to specify a default kernel config
42file name to override the default name of ".config".
43
44KCONFIG_DEFCONFIG_LIST
45----------------------
46
47This environment variable specifies a list of config files which can be used
48as a base configuration in case the .config does not exist yet. Entries in
49the list are separated with whitespaces to each other, and the first one
50that exists is used.
51
52KCONFIG_OVERWRITECONFIG
53-----------------------
54If you set KCONFIG_OVERWRITECONFIG in the environment, Kconfig will not
55break symlinks when .config is a symlink to somewhere else.
56
57`CONFIG_`
58---------
59If you set `CONFIG_` in the environment, Kconfig will prefix all symbols
60with its value when saving the configuration, instead of using the default,
61`CONFIG_`.
62
63----------------------------------------------------------------------
64
65Environment variables for '{allyes/allmod/allno/rand}config'
66
67KCONFIG_ALLCONFIG
68-----------------
69(partially based on lkml email from/by Rob Landley, re: miniconfig)
70
71--------------------------------------------------
72
73The allyesconfig/allmodconfig/allnoconfig/randconfig variants can also
74use the environment variable KCONFIG_ALLCONFIG as a flag or a filename
75that contains config symbols that the user requires to be set to a
76specific value.  If KCONFIG_ALLCONFIG is used without a filename where
77KCONFIG_ALLCONFIG == "" or KCONFIG_ALLCONFIG == "1", `make *config`
78checks for a file named "all{yes/mod/no/def/random}.config"
79(corresponding to the `*config` command that was used) for symbol values
80that are to be forced.  If this file is not found, it checks for a
81file named "all.config" to contain forced values.
82
83This enables you to create "miniature" config (miniconfig) or custom
84config files containing just the config symbols that you are interested
85in.  Then the kernel config system generates the full .config file,
86including symbols of your miniconfig file.
87
88This 'KCONFIG_ALLCONFIG' file is a config file which contains
89(usually a subset of all) preset config symbols.  These variable
90settings are still subject to normal dependency checks.
91
92Examples::
93
94	KCONFIG_ALLCONFIG=custom-notebook.config make allnoconfig
95
96or::
97
98	KCONFIG_ALLCONFIG=mini.config make allnoconfig
99
100or::
101
102	make KCONFIG_ALLCONFIG=mini.config allnoconfig
103
104These examples will disable most options (allnoconfig) but enable or
105disable the options that are explicitly listed in the specified
106mini-config files.
107
108----------------------------------------------------------------------
109
110Environment variables for 'randconfig'
111
112KCONFIG_SEED
113------------
114You can set this to the integer value used to seed the RNG, if you want
115to somehow debug the behaviour of the kconfig parser/frontends.
116If not set, the current time will be used.
117
118KCONFIG_PROBABILITY
119-------------------
120This variable can be used to skew the probabilities. This variable can
121be unset or empty, or set to three different formats:
122
123    =======================     ==================  =====================
124	KCONFIG_PROBABILITY     y:n split           y:m:n split
125    =======================     ==================  =====================
126	unset or empty          50  : 50            33  : 33  : 34
127	N                        N  : 100-N         N/2 : N/2 : 100-N
128    [1] N:M                     N+M : 100-(N+M)      N  :  M  : 100-(N+M)
129    [2] N:M:L                    N  : 100-N          M  :  L  : 100-(M+L)
130    =======================     ==================  =====================
131
132where N, M and L are integers (in base 10) in the range [0,100], and so
133that:
134
135    [1] N+M is in the range [0,100]
136
137    [2] M+L is in the range [0,100]
138
139Examples::
140
141	KCONFIG_PROBABILITY=10
142		10% of booleans will be set to 'y', 90% to 'n'
143		5% of tristates will be set to 'y', 5% to 'm', 90% to 'n'
144	KCONFIG_PROBABILITY=15:25
145		40% of booleans will be set to 'y', 60% to 'n'
146		15% of tristates will be set to 'y', 25% to 'm', 60% to 'n'
147	KCONFIG_PROBABILITY=10:15:15
148		10% of booleans will be set to 'y', 90% to 'n'
149		15% of tristates will be set to 'y', 15% to 'm', 70% to 'n'
150
151----------------------------------------------------------------------
152
153Environment variables for 'syncconfig'
154
155KCONFIG_NOSILENTUPDATE
156----------------------
157If this variable has a non-blank value, it prevents silent kernel
158config updates (requires explicit updates).
159
160KCONFIG_AUTOCONFIG
161------------------
162This environment variable can be set to specify the path & name of the
163"auto.conf" file.  Its default value is "include/config/auto.conf".
164
165KCONFIG_AUTOHEADER
166------------------
167This environment variable can be set to specify the path & name of the
168"autoconf.h" (header) file.
169Its default value is "include/generated/autoconf.h".
170
171
172----------------------------------------------------------------------
173
174menuconfig
175----------
176
177SEARCHING for CONFIG symbols
178
179Searching in menuconfig:
180
181	The Search function searches for kernel configuration symbol
182	names, so you have to know something close to what you are
183	looking for.
184
185	Example::
186
187		/hotplug
188		This lists all config symbols that contain "hotplug",
189		e.g., HOTPLUG_CPU, MEMORY_HOTPLUG.
190
191	For search help, enter / followed by TAB-TAB (to highlight
192	<Help>) and Enter.  This will tell you that you can also use
193	regular expressions (regexes) in the search string, so if you
194	are not interested in MEMORY_HOTPLUG, you could try::
195
196		/^hotplug
197
198	When searching, symbols are sorted thus:
199
200	  - first, exact matches, sorted alphabetically (an exact match
201	    is when the search matches the complete symbol name);
202	  - then, other matches, sorted alphabetically.
203
204	For example: ^ATH.K matches:
205
206	    ATH5K ATH9K ATH5K_AHB ATH5K_DEBUG [...] ATH6KL ATH6KL_DEBUG
207	    [...] ATH9K_AHB ATH9K_BTCOEX_SUPPORT ATH9K_COMMON [...]
208
209	of which only ATH5K and ATH9K match exactly and so are sorted
210	first (and in alphabetical order), then come all other symbols,
211	sorted in alphabetical order.
212
213----------------------------------------------------------------------
214
215User interface options for 'menuconfig'
216
217MENUCONFIG_COLOR
218----------------
219It is possible to select different color themes using the variable
220MENUCONFIG_COLOR.  To select a theme use::
221
222	make MENUCONFIG_COLOR=<theme> menuconfig
223
224Available themes are::
225
226  - mono       => selects colors suitable for monochrome displays
227  - blackbg    => selects a color scheme with black background
228  - classic    => theme with blue background. The classic look
229  - bluetitle  => a LCD friendly version of classic. (default)
230
231MENUCONFIG_MODE
232---------------
233This mode shows all sub-menus in one large tree.
234
235Example::
236
237	make MENUCONFIG_MODE=single_menu menuconfig
238
239----------------------------------------------------------------------
240
241nconfig
242-------
243
244nconfig is an alternate text-based configurator.  It lists function
245keys across the bottom of the terminal (window) that execute commands.
246You can also just use the corresponding numeric key to execute the
247commands unless you are in a data entry window.  E.g., instead of F6
248for Save, you can just press 6.
249
250Use F1 for Global help or F3 for the Short help menu.
251
252Searching in nconfig:
253
254	You can search either in the menu entry "prompt" strings
255	or in the configuration symbols.
256
257	Use / to begin a search through the menu entries.  This does
258	not support regular expressions.  Use <Down> or <Up> for
259	Next hit and Previous hit, respectively.  Use <Esc> to
260	terminate the search mode.
261
262	F8 (SymSearch) searches the configuration symbols for the
263	given string or regular expression (regex).
264
265NCONFIG_MODE
266------------
267This mode shows all sub-menus in one large tree.
268
269Example::
270
271	make NCONFIG_MODE=single_menu nconfig
272
273----------------------------------------------------------------------
274
275xconfig
276-------
277
278Searching in xconfig:
279
280	The Search function searches for kernel configuration symbol
281	names, so you have to know something close to what you are
282	looking for.
283
284	Example::
285
286		Ctrl-F hotplug
287
288	or::
289
290		Menu: File, Search, hotplug
291
292	lists all config symbol entries that contain "hotplug" in
293	the symbol name.  In this Search dialog, you may change the
294	config setting for any of the entries that are not grayed out.
295	You can also enter a different search string without having
296	to return to the main menu.
297
298
299----------------------------------------------------------------------
300
301gconfig
302-------
303
304Searching in gconfig:
305
306	There is no search command in gconfig.  However, gconfig does
307	have several different viewing choices, modes, and options.
308