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1This file contains some assistance for using "make *config".
2
3Use "make help" to list all of the possible configuration targets.
4
5The xconfig ('qconf') and menuconfig ('mconf') programs also
6have embedded help text. Be sure to check it for navigation,
7search, and other general help text.
8
9======================================================================
10General
11--------------------------------------------------
12
13New kernel releases often introduce new config symbols. Often more
14important, new kernel releases may rename config symbols. When
15this happens, using a previously working .config file and running
16"make oldconfig" won't necessarily produce a working new kernel
17for you, so you may find that you need to see what NEW kernel
18symbols have been introduced.
19
20To see a list of new config symbols when using "make oldconfig", use
21
22 cp user/some/old.config .config
23 yes "" | make oldconfig >conf.new
24
25and the config program will list as (NEW) any new symbols that have
26unknown values. Of course, the .config file is also updated with
27new (default) values, so you can use:
28
29 grep "(NEW)" conf.new
30
31to see the new config symbols or you can use diffconfig to see the
32differences between the previous and new .config files:
33
34 scripts/diffconfig .config.old .config | less
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_OVERWRITECONFIG
45--------------------------------------------------
46If you set KCONFIG_OVERWRITECONFIG in the environment, Kconfig will not
47break symlinks when .config is a symlink to somewhere else.
48
49CONFIG_
50--------------------------------------------------
51If you set CONFIG_ in the environment, Kconfig will prefix all symbols
52with its value when saving the configuration, instead of using the default,
53"CONFIG_".
54
55______________________________________________________________________
56Environment variables for '{allyes/allmod/allno/rand}config'
57
58KCONFIG_ALLCONFIG
59--------------------------------------------------
60(partially based on lkml email from/by Rob Landley, re: miniconfig)
61--------------------------------------------------
62The allyesconfig/allmodconfig/allnoconfig/randconfig variants can also
63use the environment variable KCONFIG_ALLCONFIG as a flag or a filename
64that contains config symbols that the user requires to be set to a
65specific value. If KCONFIG_ALLCONFIG is used without a filename where
66KCONFIG_ALLCONFIG == "" or KCONFIG_ALLCONFIG == "1", "make *config"
67checks for a file named "all{yes/mod/no/def/random}.config"
68(corresponding to the *config command that was used) for symbol values
69that are to be forced. If this file is not found, it checks for a
70file named "all.config" to contain forced values.
71
72This enables you to create "miniature" config (miniconfig) or custom
73config files containing just the config symbols that you are interested
74in. Then the kernel config system generates the full .config file,
75including symbols of your miniconfig file.
76
77This 'KCONFIG_ALLCONFIG' file is a config file which contains
78(usually a subset of all) preset config symbols. These variable
79settings are still subject to normal dependency checks.
80
81Examples:
82 KCONFIG_ALLCONFIG=custom-notebook.config make allnoconfig
83or
84 KCONFIG_ALLCONFIG=mini.config make allnoconfig
85or
86 make KCONFIG_ALLCONFIG=mini.config allnoconfig
87
88These examples will disable most options (allnoconfig) but enable or
89disable the options that are explicitly listed in the specified
90mini-config files.
91
92______________________________________________________________________
93Environment variables for 'silentoldconfig'
94
95KCONFIG_NOSILENTUPDATE
96--------------------------------------------------
97If this variable has a non-blank value, it prevents silent kernel
98config updates (requires explicit updates).
99
100KCONFIG_AUTOCONFIG
101--------------------------------------------------
102This environment variable can be set to specify the path & name of the
103"auto.conf" file. Its default value is "include/config/auto.conf".
104
105KCONFIG_TRISTATE
106--------------------------------------------------
107This environment variable can be set to specify the path & name of the
108"tristate.conf" file. Its default value is "include/config/tristate.conf".
109
110KCONFIG_AUTOHEADER
111--------------------------------------------------
112This environment variable can be set to specify the path & name of the
113"autoconf.h" (header) file.
114Its default value is "include/generated/autoconf.h".
115
116
117======================================================================
118menuconfig
119--------------------------------------------------
120
121SEARCHING for CONFIG symbols
122
123Searching in menuconfig:
124
125 The Search function searches for kernel configuration symbol
126 names, so you have to know something close to what you are
127 looking for.
128
129 Example:
130 /hotplug
131 This lists all config symbols that contain "hotplug",
132 e.g., HOTPLUG, HOTPLUG_CPU, MEMORY_HOTPLUG.
133
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
138
139 /^hotplug
140
141______________________________________________________________________
142User interface options for 'menuconfig'
143
144MENUCONFIG_COLOR
145--------------------------------------------------
146It is possible to select different color themes using the variable
147MENUCONFIG_COLOR. To select a theme use:
148
149 make MENUCONFIG_COLOR=<theme> menuconfig
150
151Available 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)
156
157MENUCONFIG_MODE
158--------------------------------------------------
159This mode shows all sub-menus in one large tree.
160
161Example:
162 make MENUCONFIG_MODE=single_menu menuconfig
163
164
165======================================================================
166xconfig
167--------------------------------------------------
168
169Searching in xconfig:
170
171 The Search function searches for kernel configuration symbol
172 names, so you have to know something close to what you are
173 looking for.
174
175 Example:
176 Ctrl-F hotplug
177 or
178 Menu: File, Search, hotplug
179
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.
185
186
187======================================================================
188gconfig
189--------------------------------------------------
190
191Searching in gconfig:
192
193 None (gconfig isn't maintained as well as xconfig or menuconfig);
194 however, gconfig does have a few more viewing choices than
195 xconfig does.
196
197###