kconfig.rst (9610B)
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.