1 This file contains some assistance for using "make *config".
3 Use "make help" to list all of the possible configuration targets.
5 The xconfig ('qconf'), menuconfig ('mconf'), and nconfig ('nconf')
6 programs also have embedded help text. Be sure to check that for
7 navigation, search, and other general help text.
9 ======================================================================
11 --------------------------------------------------
13 New kernel releases often introduce new config symbols. Often more
14 important, new kernel releases may rename config symbols. When
15 this happens, using a previously working .config file and running
16 "make oldconfig" won't necessarily produce a working new kernel
17 for you, so you may find that you need to see what NEW kernel
18 symbols have been introduced.
20 To see a list of new config symbols, use
22 cp user/some/old.config .config
25 and the config program will list any new symbols, one per line.
27 Alternatively, you can use the brute force method:
30 scripts/diffconfig .config.old .config | less
32 ______________________________________________________________________
33 Environment variables for '*config'
36 --------------------------------------------------
37 This environment variable can be used to specify a default kernel config
38 file name to override the default name of ".config".
40 KCONFIG_OVERWRITECONFIG
41 --------------------------------------------------
42 If you set KCONFIG_OVERWRITECONFIG in the environment, Kconfig will not
43 break symlinks when .config is a symlink to somewhere else.
46 --------------------------------------------------
47 If you set CONFIG_ in the environment, Kconfig will prefix all symbols
48 with its value when saving the configuration, instead of using the default,
51 ______________________________________________________________________
52 Environment variables for '{allyes/allmod/allno/rand}config'
55 --------------------------------------------------
56 (partially based on lkml email from/by Rob Landley, re: miniconfig)
57 --------------------------------------------------
58 The allyesconfig/allmodconfig/allnoconfig/randconfig variants can also
59 use the environment variable KCONFIG_ALLCONFIG as a flag or a filename
60 that contains config symbols that the user requires to be set to a
61 specific value. If KCONFIG_ALLCONFIG is used without a filename where
62 KCONFIG_ALLCONFIG == "" or KCONFIG_ALLCONFIG == "1", "make *config"
63 checks for a file named "all{yes/mod/no/def/random}.config"
64 (corresponding to the *config command that was used) for symbol values
65 that are to be forced. If this file is not found, it checks for a
66 file named "all.config" to contain forced values.
68 This enables you to create "miniature" config (miniconfig) or custom
69 config files containing just the config symbols that you are interested
70 in. Then the kernel config system generates the full .config file,
71 including symbols of your miniconfig file.
73 This 'KCONFIG_ALLCONFIG' file is a config file which contains
74 (usually a subset of all) preset config symbols. These variable
75 settings are still subject to normal dependency checks.
78 KCONFIG_ALLCONFIG=custom-notebook.config make allnoconfig
80 KCONFIG_ALLCONFIG=mini.config make allnoconfig
82 make KCONFIG_ALLCONFIG=mini.config allnoconfig
84 These examples will disable most options (allnoconfig) but enable or
85 disable the options that are explicitly listed in the specified
88 ______________________________________________________________________
89 Environment variables for 'randconfig'
92 --------------------------------------------------
93 You can set this to the integer value used to seed the RNG, if you want
94 to somehow debug the behaviour of the kconfig parser/frontends.
95 If not set, the current time will be used.
98 --------------------------------------------------
99 This variable can be used to skew the probabilities. This variable can
100 be unset or empty, or set to three different formats:
101 KCONFIG_PROBABILITY y:n split y:m:n split
102 -----------------------------------------------------------------
103 unset or empty 50 : 50 33 : 33 : 34
104 N N : 100-N N/2 : N/2 : 100-N
105 [1] N:M N+M : 100-(N+M) N : M : 100-(N+M)
106 [2] N:M:L N : 100-N M : L : 100-(M+L)
108 where N, M and L are integers (in base 10) in the range [0,100], and so
110 [1] N+M is in the range [0,100]
111 [2] M+L is in the range [0,100]
114 KCONFIG_PROBABILITY=10
115 10% of booleans will be set to 'y', 90% to 'n'
116 5% of tristates will be set to 'y', 5% to 'm', 90% to 'n'
117 KCONFIG_PROBABILITY=15:25
118 40% of booleans will be set to 'y', 60% to 'n'
119 15% of tristates will be set to 'y', 25% to 'm', 60% to 'n'
120 KCONFIG_PROBABILITY=10:15:15
121 10% of booleans will be set to 'y', 90% to 'n'
122 15% of tristates will be set to 'y', 15% to 'm', 70% to 'n'
124 ______________________________________________________________________
125 Environment variables for 'syncconfig'
127 KCONFIG_NOSILENTUPDATE
128 --------------------------------------------------
129 If this variable has a non-blank value, it prevents silent kernel
130 config updates (requires explicit updates).
133 --------------------------------------------------
134 This environment variable can be set to specify the path & name of the
135 "auto.conf" file. Its default value is "include/config/auto.conf".
138 --------------------------------------------------
139 This environment variable can be set to specify the path & name of the
140 "tristate.conf" file. Its default value is "include/config/tristate.conf".
143 --------------------------------------------------
144 This environment variable can be set to specify the path & name of the
145 "autoconf.h" (header) file.
146 Its default value is "include/generated/autoconf.h".
149 ======================================================================
151 --------------------------------------------------
153 SEARCHING for CONFIG symbols
155 Searching in menuconfig:
157 The Search function searches for kernel configuration symbol
158 names, so you have to know something close to what you are
163 This lists all config symbols that contain "hotplug",
164 e.g., HOTPLUG_CPU, MEMORY_HOTPLUG.
166 For search help, enter / followed by TAB-TAB (to highlight
167 <Help>) and Enter. This will tell you that you can also use
168 regular expressions (regexes) in the search string, so if you
169 are not interested in MEMORY_HOTPLUG, you could try
173 When searching, symbols are sorted thus:
174 - first, exact matches, sorted alphabetically (an exact match
175 is when the search matches the complete symbol name);
176 - then, other matches, sorted alphabetically.
177 For example: ^ATH.K matches:
178 ATH5K ATH9K ATH5K_AHB ATH5K_DEBUG [...] ATH6KL ATH6KL_DEBUG
179 [...] ATH9K_AHB ATH9K_BTCOEX_SUPPORT ATH9K_COMMON [...]
180 of which only ATH5K and ATH9K match exactly and so are sorted
181 first (and in alphabetical order), then come all other symbols,
182 sorted in alphabetical order.
184 ______________________________________________________________________
185 User interface options for 'menuconfig'
188 --------------------------------------------------
189 It is possible to select different color themes using the variable
190 MENUCONFIG_COLOR. To select a theme use:
192 make MENUCONFIG_COLOR=<theme> menuconfig
194 Available themes are:
195 mono => selects colors suitable for monochrome displays
196 blackbg => selects a color scheme with black background
197 classic => theme with blue background. The classic look
198 bluetitle => a LCD friendly version of classic. (default)
201 --------------------------------------------------
202 This mode shows all sub-menus in one large tree.
205 make MENUCONFIG_MODE=single_menu menuconfig
208 ======================================================================
210 --------------------------------------------------
212 nconfig is an alternate text-based configurator. It lists function
213 keys across the bottom of the terminal (window) that execute commands.
214 You can also just use the corresponding numeric key to execute the
215 commands unless you are in a data entry window. E.g., instead of F6
216 for Save, you can just press 6.
218 Use F1 for Global help or F3 for the Short help menu.
220 Searching in nconfig:
222 You can search either in the menu entry "prompt" strings
223 or in the configuration symbols.
225 Use / to begin a search through the menu entries. This does
226 not support regular expressions. Use <Down> or <Up> for
227 Next hit and Previous hit, respectively. Use <Esc> to
228 terminate the search mode.
230 F8 (SymSearch) searches the configuration symbols for the
231 given string or regular expression (regex).
234 --------------------------------------------------
235 This mode shows all sub-menus in one large tree.
238 make NCONFIG_MODE=single_menu nconfig
241 ======================================================================
243 --------------------------------------------------
245 Searching in xconfig:
247 The Search function searches for kernel configuration symbol
248 names, so you have to know something close to what you are
254 Menu: File, Search, hotplug
256 lists all config symbol entries that contain "hotplug" in
257 the symbol name. In this Search dialog, you may change the
258 config setting for any of the entries that are not grayed out.
259 You can also enter a different search string without having
260 to return to the main menu.
263 ======================================================================
265 --------------------------------------------------
267 Searching in gconfig:
269 There is no search command in gconfig. However, gconfig does
270 have several different viewing choices, modes, and options.