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.
59 If you set `CONFIG_` in the environment, Kconfig will prefix all symbols
60 with its value when saving the configuration, instead of using the default,
63 ----------------------------------------------------------------------
65 Environment variables for '{allyes/allmod/allno/rand}config'
69 (partially based on lkml email from/by Rob Landley, re: miniconfig)
71 --------------------------------------------------
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.
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.
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.
94 KCONFIG_ALLCONFIG=custom-notebook.config make allnoconfig
98 KCONFIG_ALLCONFIG=mini.config make allnoconfig
102 make KCONFIG_ALLCONFIG=mini.config allnoconfig
104 These examples will disable most options (allnoconfig) but enable or
105 disable the options that are explicitly listed in the specified
108 ----------------------------------------------------------------------
110 Environment variables for 'randconfig'
114 You can set this to the integer value used to seed the RNG, if you want
115 to somehow debug the behaviour of the kconfig parser/frontends.
116 If not set, the current time will be used.
120 This variable can be used to skew the probabilities. This variable can
121 be unset or empty, or set to three different formats:
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 ======================= ================== =====================
132 where N, M and L are integers (in base 10) in the range [0,100], and so
135 [1] N+M is in the range [0,100]
137 [2] M+L is in the range [0,100]
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'
151 ----------------------------------------------------------------------
153 Environment variables for 'syncconfig'
155 KCONFIG_NOSILENTUPDATE
156 ----------------------
157 If this variable has a non-blank value, it prevents silent kernel
158 config updates (requires explicit updates).
162 This environment variable can be set to specify the path & name of the
163 "auto.conf" file. Its default value is "include/config/auto.conf".
167 This environment variable can be set to specify the path & name of the
168 "autoconf.h" (header) file.
169 Its default value is "include/generated/autoconf.h".
172 ----------------------------------------------------------------------
177 SEARCHING for CONFIG symbols
179 Searching in menuconfig:
181 The Search function searches for kernel configuration symbol
182 names, so you have to know something close to what you are
188 This lists all config symbols that contain "hotplug",
189 e.g., HOTPLUG_CPU, MEMORY_HOTPLUG.
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::
198 When searching, symbols are sorted thus:
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.
204 For example: ^ATH.K matches:
206 ATH5K ATH9K ATH5K_AHB ATH5K_DEBUG [...] ATH6KL ATH6KL_DEBUG
207 [...] ATH9K_AHB ATH9K_BTCOEX_SUPPORT ATH9K_COMMON [...]
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.
213 In this menu, pressing the key in the (#) prefix will jump
214 directly to that location. You will be returned to the current
215 search results after exiting this new menu.
217 ----------------------------------------------------------------------
219 User interface options for 'menuconfig'
223 It is possible to select different color themes using the variable
224 MENUCONFIG_COLOR. To select a theme use::
226 make MENUCONFIG_COLOR=<theme> menuconfig
228 Available themes are::
230 - mono => selects colors suitable for monochrome displays
231 - blackbg => selects a color scheme with black background
232 - classic => theme with blue background. The classic look
233 - bluetitle => a LCD friendly version of classic. (default)
237 This mode shows all sub-menus in one large tree.
241 make MENUCONFIG_MODE=single_menu menuconfig
243 ----------------------------------------------------------------------
248 nconfig is an alternate text-based configurator. It lists function
249 keys across the bottom of the terminal (window) that execute commands.
250 You can also just use the corresponding numeric key to execute the
251 commands unless you are in a data entry window. E.g., instead of F6
252 for Save, you can just press 6.
254 Use F1 for Global help or F3 for the Short help menu.
256 Searching in nconfig:
258 You can search either in the menu entry "prompt" strings
259 or in the configuration symbols.
261 Use / to begin a search through the menu entries. This does
262 not support regular expressions. Use <Down> or <Up> for
263 Next hit and Previous hit, respectively. Use <Esc> to
264 terminate the search mode.
266 F8 (SymSearch) searches the configuration symbols for the
267 given string or regular expression (regex).
269 In the SymSearch, pressing the key in the (#) prefix will
270 jump directly to that location. You will be returned to the
271 current search results after exiting this new menu.
275 This mode shows all sub-menus in one large tree.
279 make NCONFIG_MODE=single_menu nconfig
281 ----------------------------------------------------------------------
286 Searching in xconfig:
288 The Search function searches for kernel configuration symbol
289 names, so you have to know something close to what you are
298 Menu: File, Search, hotplug
300 lists all config symbol entries that contain "hotplug" in
301 the symbol name. In this Search dialog, you may change the
302 config setting for any of the entries that are not grayed out.
303 You can also enter a different search string without having
304 to return to the main menu.
307 ----------------------------------------------------------------------
312 Searching in gconfig:
314 There is no search command in gconfig. However, gconfig does
315 have several different viewing choices, modes, and options.