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.
13 The gconfig ('gconf') program has limited help text.
18 New kernel releases often introduce new config symbols. Often more
19 important, new kernel releases may rename config symbols. When
20 this happens, using a previously working .config file and running
21 "make oldconfig" won't necessarily produce a working new kernel
22 for you, so you may find that you need to see what NEW kernel
23 symbols have been introduced.
25 To see a list of new config symbols, use::
27 cp user/some/old.config .config
30 and the config program will list any new symbols, one per line.
32 Alternatively, you can use the brute force method::
35 scripts/diffconfig .config.old .config | less
37 ----------------------------------------------------------------------
39 Environment variables for `*config`
43 This environment variable can be used to specify a default kernel config
44 file name to override the default name of ".config".
46 KCONFIG_DEFCONFIG_LIST
47 ----------------------
49 This environment variable specifies a list of config files which can be used
50 as a base configuration in case the .config does not exist yet. Entries in
51 the list are separated with whitespaces to each other, and the first one
54 KCONFIG_OVERWRITECONFIG
55 -----------------------
56 If you set KCONFIG_OVERWRITECONFIG in the environment, Kconfig will not
57 break symlinks when .config is a symlink to somewhere else.
59 KCONFIG_WARN_UNKNOWN_SYMBOLS
60 ----------------------------
61 This environment variable makes Kconfig warn about all unrecognized
62 symbols in the config input.
66 If set, Kconfig treats warnings as errors.
70 If you set `CONFIG_` in the environment, Kconfig will prefix all symbols
71 with its value when saving the configuration, instead of using the default,
74 ----------------------------------------------------------------------
76 Environment variables for '{allyes/allmod/allno/rand}config'
80 (partially based on lkml email from/by Rob Landley, re: miniconfig)
82 --------------------------------------------------
84 The allyesconfig/allmodconfig/allnoconfig/randconfig variants can also
85 use the environment variable KCONFIG_ALLCONFIG as a flag or a filename
86 that contains config symbols that the user requires to be set to a
87 specific value. If KCONFIG_ALLCONFIG is used without a filename where
88 KCONFIG_ALLCONFIG == "" or KCONFIG_ALLCONFIG == "1", `make *config`
89 checks for a file named "all{yes/mod/no/def/random}.config"
90 (corresponding to the `*config` command that was used) for symbol values
91 that are to be forced. If this file is not found, it checks for a
92 file named "all.config" to contain forced values.
94 This enables you to create "miniature" config (miniconfig) or custom
95 config files containing just the config symbols that you are interested
96 in. Then the kernel config system generates the full .config file,
97 including symbols of your miniconfig file.
99 This 'KCONFIG_ALLCONFIG' file is a config file which contains
100 (usually a subset of all) preset config symbols. These variable
101 settings are still subject to normal dependency checks.
105 KCONFIG_ALLCONFIG=custom-notebook.config make allnoconfig
109 KCONFIG_ALLCONFIG=mini.config make allnoconfig
113 make KCONFIG_ALLCONFIG=mini.config allnoconfig
115 These examples will disable most options (allnoconfig) but enable or
116 disable the options that are explicitly listed in the specified
119 ----------------------------------------------------------------------
121 Environment variables for 'randconfig'
125 You can set this to the integer value used to seed the RNG, if you want
126 to somehow debug the behaviour of the kconfig parser/frontends.
127 If not set, the current time will be used.
131 This variable can be used to skew the probabilities. This variable can
132 be unset or empty, or set to three different formats:
134 ======================= ================== =====================
135 KCONFIG_PROBABILITY y:n split y:m:n split
136 ======================= ================== =====================
137 unset or empty 50 : 50 33 : 33 : 34
138 N N : 100-N N/2 : N/2 : 100-N
139 [1] N:M N+M : 100-(N+M) N : M : 100-(N+M)
140 [2] N:M:L N : 100-N M : L : 100-(M+L)
141 ======================= ================== =====================
143 where N, M and L are integers (in base 10) in the range [0,100], and so
146 [1] N+M is in the range [0,100]
148 [2] M+L is in the range [0,100]
152 KCONFIG_PROBABILITY=10
153 10% of booleans will be set to 'y', 90% to 'n'
154 5% of tristates will be set to 'y', 5% to 'm', 90% to 'n'
155 KCONFIG_PROBABILITY=15:25
156 40% of booleans will be set to 'y', 60% to 'n'
157 15% of tristates will be set to 'y', 25% to 'm', 60% to 'n'
158 KCONFIG_PROBABILITY=10:15:15
159 10% of booleans will be set to 'y', 90% to 'n'
160 15% of tristates will be set to 'y', 15% to 'm', 70% to 'n'
162 ----------------------------------------------------------------------
164 Environment variables for 'syncconfig'
166 KCONFIG_NOSILENTUPDATE
167 ----------------------
168 If this variable has a non-blank value, it prevents silent kernel
169 config updates (requires explicit updates).
173 This environment variable can be set to specify the path & name of the
174 "auto.conf" file. Its default value is "include/config/auto.conf".
178 This environment variable can be set to specify the path & name of the
179 "autoconf.h" (header) file.
180 Its default value is "include/generated/autoconf.h".
183 ----------------------------------------------------------------------
188 SEARCHING for CONFIG symbols
190 Searching in menuconfig:
192 The Search function searches for kernel configuration symbol
193 names, so you have to know something close to what you are
199 This lists all config symbols that contain "hotplug",
200 e.g., HOTPLUG_CPU, MEMORY_HOTPLUG.
202 For search help, enter / followed by TAB-TAB (to highlight
203 <Help>) and Enter. This will tell you that you can also use
204 regular expressions (regexes) in the search string, so if you
205 are not interested in MEMORY_HOTPLUG, you could try::
209 When searching, symbols are sorted thus:
211 - first, exact matches, sorted alphabetically (an exact match
212 is when the search matches the complete symbol name);
213 - then, other matches, sorted alphabetically.
215 For example: ^ATH.K matches:
217 ATH5K ATH9K ATH5K_AHB ATH5K_DEBUG [...] ATH6KL ATH6KL_DEBUG
218 [...] ATH9K_AHB ATH9K_BTCOEX_SUPPORT ATH9K_COMMON [...]
220 of which only ATH5K and ATH9K match exactly and so are sorted
221 first (and in alphabetical order), then come all other symbols,
222 sorted in alphabetical order.
224 In this menu, pressing the key in the (#) prefix will jump
225 directly to that location. You will be returned to the current
226 search results after exiting this new menu.
228 ----------------------------------------------------------------------
230 User interface options for 'menuconfig'
234 It is possible to select different color themes using the variable
235 MENUCONFIG_COLOR. To select a theme use::
237 make MENUCONFIG_COLOR=<theme> menuconfig
239 Available themes are::
241 - mono => selects colors suitable for monochrome displays
242 - blackbg => selects a color scheme with black background
243 - classic => theme with blue background. The classic look
244 - bluetitle => a LCD friendly version of classic. (default)
248 This mode shows all sub-menus in one large tree.
252 make MENUCONFIG_MODE=single_menu menuconfig
254 ----------------------------------------------------------------------
259 nconfig is an alternate text-based configurator. It lists function
260 keys across the bottom of the terminal (window) that execute commands.
261 You can also just use the corresponding numeric key to execute the
262 commands unless you are in a data entry window. E.g., instead of F6
263 for Save, you can just press 6.
265 Use F1 for Global help or F3 for the Short help menu.
267 Searching in nconfig:
269 You can search either in the menu entry "prompt" strings
270 or in the configuration symbols.
272 Use / to begin a search through the menu entries. This does
273 not support regular expressions. Use <Down> or <Up> for
274 Next hit and Previous hit, respectively. Use <Esc> to
275 terminate the search mode.
277 F8 (SymSearch) searches the configuration symbols for the
278 given string or regular expression (regex).
280 In the SymSearch, pressing the key in the (#) prefix will
281 jump directly to that location. You will be returned to the
282 current search results after exiting this new menu.
286 This mode shows all sub-menus in one large tree.
290 make NCONFIG_MODE=single_menu nconfig
292 ----------------------------------------------------------------------
297 Searching in xconfig:
299 The Search function searches for kernel configuration symbol
300 names, so you have to know something close to what you are
309 Menu: File, Search, hotplug
311 lists all config symbol entries that contain "hotplug" in
312 the symbol name. In this Search dialog, you may change the
313 config setting for any of the entries that are not grayed out.
314 You can also enter a different search string without having
315 to return to the main menu.
318 ----------------------------------------------------------------------
323 Searching in gconfig:
325 There is no search command in gconfig. However, gconfig does
326 have several different viewing choices, modes, and options.