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') and menuconfig ('mconf') programs also
6 have embedded help text. Be sure to check it for navigation,
7 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 when using "make oldconfig", use
22 cp user/some/old.config .config
23 yes "" | make oldconfig >conf.new
25 and the config program will list as (NEW) any new symbols that have
26 unknown values. Of course, the .config file is also updated with
27 new (default) values, so you can use:
31 to see the new config symbols or you can use diffconfig to see the
32 differences between the previous and new .config files:
34 scripts/diffconfig .config.old .config | less
36 ______________________________________________________________________
37 Environment variables for '*config'
40 --------------------------------------------------
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_OVERWRITECONFIG
45 --------------------------------------------------
46 If you set KCONFIG_OVERWRITECONFIG in the environment, Kconfig will not
47 break symlinks when .config is a symlink to somewhere else.
50 --------------------------------------------------
51 If you set CONFIG_ in the environment, Kconfig will prefix all symbols
52 with its value when saving the configuration, instead of using the default,
55 ______________________________________________________________________
56 Environment variables for '{allyes/allmod/allno/rand}config'
59 --------------------------------------------------
60 (partially based on lkml email from/by Rob Landley, re: miniconfig)
61 --------------------------------------------------
62 The allyesconfig/allmodconfig/allnoconfig/randconfig variants can also
63 use the environment variable KCONFIG_ALLCONFIG as a flag or a filename
64 that contains config symbols that the user requires to be set to a
65 specific value. If KCONFIG_ALLCONFIG is used without a filename where
66 KCONFIG_ALLCONFIG == "" or KCONFIG_ALLCONFIG == "1", "make *config"
67 checks for a file named "all{yes/mod/no/def/random}.config"
68 (corresponding to the *config command that was used) for symbol values
69 that are to be forced. If this file is not found, it checks for a
70 file named "all.config" to contain forced values.
72 This enables you to create "miniature" config (miniconfig) or custom
73 config files containing just the config symbols that you are interested
74 in. Then the kernel config system generates the full .config file,
75 including symbols of your miniconfig file.
77 This 'KCONFIG_ALLCONFIG' file is a config file which contains
78 (usually a subset of all) preset config symbols. These variable
79 settings are still subject to normal dependency checks.
82 KCONFIG_ALLCONFIG=custom-notebook.config make allnoconfig
84 KCONFIG_ALLCONFIG=mini.config make allnoconfig
86 make KCONFIG_ALLCONFIG=mini.config allnoconfig
88 These examples will disable most options (allnoconfig) but enable or
89 disable the options that are explicitly listed in the specified
92 ______________________________________________________________________
93 Environment variables for 'silentoldconfig'
95 KCONFIG_NOSILENTUPDATE
96 --------------------------------------------------
97 If this variable has a non-blank value, it prevents silent kernel
98 config updates (requires explicit updates).
101 --------------------------------------------------
102 This environment variable can be set to specify the path & name of the
103 "auto.conf" file. Its default value is "include/config/auto.conf".
106 --------------------------------------------------
107 This environment variable can be set to specify the path & name of the
108 "tristate.conf" file. Its default value is "include/config/tristate.conf".
111 --------------------------------------------------
112 This environment variable can be set to specify the path & name of the
113 "autoconf.h" (header) file.
114 Its default value is "include/generated/autoconf.h".
117 ======================================================================
119 --------------------------------------------------
121 SEARCHING for CONFIG symbols
123 Searching in menuconfig:
125 The Search function searches for kernel configuration symbol
126 names, so you have to know something close to what you are
131 This lists all config symbols that contain "hotplug",
132 e.g., HOTPLUG, HOTPLUG_CPU, MEMORY_HOTPLUG.
134 For search help, enter / followed TAB-TAB-TAB (to highlight
135 <Help>) and Enter. This will tell you that you can also use
136 regular expressions (regexes) in the search string, so if you
137 are not interested in MEMORY_HOTPLUG, you could try
141 ______________________________________________________________________
142 User interface options for 'menuconfig'
145 --------------------------------------------------
146 It is possible to select different color themes using the variable
147 MENUCONFIG_COLOR. To select a theme use:
149 make MENUCONFIG_COLOR=<theme> menuconfig
151 Available themes are:
152 mono => selects colors suitable for monochrome displays
153 blackbg => selects a color scheme with black background
154 classic => theme with blue background. The classic look
155 bluetitle => a LCD friendly version of classic. (default)
158 --------------------------------------------------
159 This mode shows all sub-menus in one large tree.
162 make MENUCONFIG_MODE=single_menu menuconfig
165 ======================================================================
167 --------------------------------------------------
169 Searching in xconfig:
171 The Search function searches for kernel configuration symbol
172 names, so you have to know something close to what you are
178 Menu: File, Search, hotplug
180 lists all config symbol entries that contain "hotplug" in
181 the symbol name. In this Search dialog, you may change the
182 config setting for any of the entries that are not grayed out.
183 You can also enter a different search string without having
184 to return to the main menu.
187 ======================================================================
189 --------------------------------------------------
191 Searching in gconfig:
193 None (gconfig isn't maintained as well as xconfig or menuconfig);
194 however, gconfig does have a few more viewing choices than