5 This file contains some assistance for using `make *config`.
7 Use "make help" to list all of the possible configuration targets.
9 The xconfig ('qconf'), menuconfig ('mconf'), and nconfig ('nconf')
10 programs also have embedded help text. Be sure to check that for
11 navigation, search, and other general help text.
16 New kernel releases often introduce new config symbols. Often more
17 important, new kernel releases may rename config symbols. When
18 this happens, using a previously working .config file and running
19 "make oldconfig" won't necessarily produce a working new kernel
20 for you, so you may find that you need to see what NEW kernel
21 symbols have been introduced.
23 To see a list of new config symbols, use::
25 cp user/some/old.config .config
28 and the config program will list any new symbols, one per line.
30 Alternatively, you can use the brute force method::
33 scripts/diffconfig .config.old .config | less
35 ----------------------------------------------------------------------
37 Environment variables for `*config`
41 This environment variable can be used to specify a default kernel config
42 file name to override the default name of ".config".
44 KCONFIG_DEFCONFIG_LIST
45 ----------------------
47 This environment variable specifies a list of config files which can be used
48 as a base configuration in case the .config does not exist yet. Entries in
49 the list are separated with whitespaces to each other, and the first one
52 KCONFIG_OVERWRITECONFIG
53 -----------------------
54 If you set KCONFIG_OVERWRITECONFIG in the environment, Kconfig will not
55 break symlinks when .config is a symlink to somewhere else.
57 KCONFIG_WARN_UNKNOWN_SYMBOLS
58 ----------------------------
59 This environment variable makes Kconfig warn about all unrecognized
60 symbols in the config input.
64 If set, Kconfig treats warnings as errors.
68 If you set `CONFIG_` in the environment, Kconfig will prefix all symbols
69 with its value when saving the configuration, instead of using the default,
72 ----------------------------------------------------------------------
74 Environment variables for '{allyes/allmod/allno/rand}config'
78 (partially based on lkml email from/by Rob Landley, re: miniconfig)
80 --------------------------------------------------
82 The allyesconfig/allmodconfig/allnoconfig/randconfig variants can also
83 use the environment variable KCONFIG_ALLCONFIG as a flag or a filename
84 that contains config symbols that the user requires to be set to a
85 specific value. If KCONFIG_ALLCONFIG is used without a filename where
86 KCONFIG_ALLCONFIG == "" or KCONFIG_ALLCONFIG == "1", `make *config`
87 checks for a file named "all{yes/mod/no/def/random}.config"
88 (corresponding to the `*config` command that was used) for symbol values
89 that are to be forced. If this file is not found, it checks for a
90 file named "all.config" to contain forced values.
92 This enables you to create "miniature" config (miniconfig) or custom
93 config files containing just the config symbols that you are interested
94 in. Then the kernel config system generates the full .config file,
95 including symbols of your miniconfig file.
97 This 'KCONFIG_ALLCONFIG' file is a config file which contains
98 (usually a subset of all) preset config symbols. These variable
99 settings are still subject to normal dependency checks.
103 KCONFIG_ALLCONFIG=custom-notebook.config make allnoconfig
107 KCONFIG_ALLCONFIG=mini.config make allnoconfig
111 make KCONFIG_ALLCONFIG=mini.config allnoconfig
113 These examples will disable most options (allnoconfig) but enable or
114 disable the options that are explicitly listed in the specified
117 ----------------------------------------------------------------------
119 Environment variables for 'randconfig'
123 You can set this to the integer value used to seed the RNG, if you want
124 to somehow debug the behaviour of the kconfig parser/frontends.
125 If not set, the current time will be used.
129 This variable can be used to skew the probabilities. This variable can
130 be unset or empty, or set to three different formats:
132 ======================= ================== =====================
133 KCONFIG_PROBABILITY y:n split y:m:n split
134 ======================= ================== =====================
135 unset or empty 50 : 50 33 : 33 : 34
136 N N : 100-N N/2 : N/2 : 100-N
137 [1] N:M N+M : 100-(N+M) N : M : 100-(N+M)
138 [2] N:M:L N : 100-N M : L : 100-(M+L)
139 ======================= ================== =====================
141 where N, M and L are integers (in base 10) in the range [0,100], and so
144 [1] N+M is in the range [0,100]
146 [2] M+L is in the range [0,100]
150 KCONFIG_PROBABILITY=10
151 10% of booleans will be set to 'y', 90% to 'n'
152 5% of tristates will be set to 'y', 5% to 'm', 90% to 'n'
153 KCONFIG_PROBABILITY=15:25
154 40% of booleans will be set to 'y', 60% to 'n'
155 15% of tristates will be set to 'y', 25% to 'm', 60% to 'n'
156 KCONFIG_PROBABILITY=10:15:15
157 10% of booleans will be set to 'y', 90% to 'n'
158 15% of tristates will be set to 'y', 15% to 'm', 70% to 'n'
160 ----------------------------------------------------------------------
162 Environment variables for 'syncconfig'
164 KCONFIG_NOSILENTUPDATE
165 ----------------------
166 If this variable has a non-blank value, it prevents silent kernel
167 config updates (requires explicit updates).
171 This environment variable can be set to specify the path & name of the
172 "auto.conf" file. Its default value is "include/config/auto.conf".
176 This environment variable can be set to specify the path & name of the
177 "autoconf.h" (header) file.
178 Its default value is "include/generated/autoconf.h".
181 ----------------------------------------------------------------------
186 SEARCHING for CONFIG symbols
188 Searching in menuconfig:
190 The Search function searches for kernel configuration symbol
191 names, so you have to know something close to what you are
197 This lists all config symbols that contain "hotplug",
198 e.g., HOTPLUG_CPU, MEMORY_HOTPLUG.
200 For search help, enter / followed by TAB-TAB (to highlight
201 <Help>) and Enter. This will tell you that you can also use
202 regular expressions (regexes) in the search string, so if you
203 are not interested in MEMORY_HOTPLUG, you could try::
207 When searching, symbols are sorted thus:
209 - first, exact matches, sorted alphabetically (an exact match
210 is when the search matches the complete symbol name);
211 - then, other matches, sorted alphabetically.
213 For example: ^ATH.K matches:
215 ATH5K ATH9K ATH5K_AHB ATH5K_DEBUG [...] ATH6KL ATH6KL_DEBUG
216 [...] ATH9K_AHB ATH9K_BTCOEX_SUPPORT ATH9K_COMMON [...]
218 of which only ATH5K and ATH9K match exactly and so are sorted
219 first (and in alphabetical order), then come all other symbols,
220 sorted in alphabetical order.
222 In this menu, pressing the key in the (#) prefix will jump
223 directly to that location. You will be returned to the current
224 search results after exiting this new menu.
226 ----------------------------------------------------------------------
228 User interface options for 'menuconfig'
232 It is possible to select different color themes using the variable
233 MENUCONFIG_COLOR. To select a theme use::
235 make MENUCONFIG_COLOR=<theme> menuconfig
237 Available themes are::
239 - mono => selects colors suitable for monochrome displays
240 - blackbg => selects a color scheme with black background
241 - classic => theme with blue background. The classic look
242 - bluetitle => a LCD friendly version of classic. (default)
246 This mode shows all sub-menus in one large tree.
250 make MENUCONFIG_MODE=single_menu menuconfig
252 ----------------------------------------------------------------------
257 nconfig is an alternate text-based configurator. It lists function
258 keys across the bottom of the terminal (window) that execute commands.
259 You can also just use the corresponding numeric key to execute the
260 commands unless you are in a data entry window. E.g., instead of F6
261 for Save, you can just press 6.
263 Use F1 for Global help or F3 for the Short help menu.
265 Searching in nconfig:
267 You can search either in the menu entry "prompt" strings
268 or in the configuration symbols.
270 Use / to begin a search through the menu entries. This does
271 not support regular expressions. Use <Down> or <Up> for
272 Next hit and Previous hit, respectively. Use <Esc> to
273 terminate the search mode.
275 F8 (SymSearch) searches the configuration symbols for the
276 given string or regular expression (regex).
278 In the SymSearch, pressing the key in the (#) prefix will
279 jump directly to that location. You will be returned to the
280 current search results after exiting this new menu.
284 This mode shows all sub-menus in one large tree.
288 make NCONFIG_MODE=single_menu nconfig
290 ----------------------------------------------------------------------
295 Searching in xconfig:
297 The Search function searches for kernel configuration symbol
298 names, so you have to know something close to what you are
307 Menu: File, Search, hotplug
309 lists all config symbol entries that contain "hotplug" in
310 the symbol name. In this Search dialog, you may change the
311 config setting for any of the entries that are not grayed out.
312 You can also enter a different search string without having
313 to return to the main menu.
316 ----------------------------------------------------------------------
321 Searching in gconfig:
323 There is no search command in gconfig. However, gconfig does
324 have several different viewing choices, modes, and options.