Documentation/kbuild/kconfig.txt - arm/linux - Git at Google


            
            This file contains some assistance for using "make *config".


            Use "make help" to list all of the possible configuration targets.


            The xconfig ('qconf') and menuconfig ('mconf') programs also

            
            have embedded help text.  Be sure to check it for navigation,

            
            search, and other general help text.


            ======================================================================

            
            General

            
            --------------------------------------------------


            New kernel releases often introduce new config symbols.  Often more

            
            important, new kernel releases may rename config symbols.  When

            
            this happens, using a previously working .config file and running

            
            "make oldconfig" won't necessarily produce a working new kernel

            
            for you, so you may find that you need to see what NEW kernel

            
            symbols have been introduced.


            To see a list of new config symbols when using "make oldconfig", use


            	cp user/some/old.config .config

            
            	make listnewconfig


            and the config program will list any new symbols, one per line.


            	scripts/diffconfig .config.old .config | less


            ______________________________________________________________________

            
            Environment variables for '*config'


            KCONFIG_CONFIG

            
            --------------------------------------------------

            
            This environment variable can be used to specify a default kernel config

            
            file name to override the default name of ".config".


            KCONFIG_OVERWRITECONFIG

            
            --------------------------------------------------

            
            If you set KCONFIG_OVERWRITECONFIG in the environment, Kconfig will not

            
            break symlinks when .config is a symlink to somewhere else.


            CONFIG_

            
            --------------------------------------------------

            
            If you set CONFIG_ in the environment, Kconfig will prefix all symbols

            
            with its value when saving the configuration, instead of using the default,

            
            "CONFIG_".


            ______________________________________________________________________

            
            Environment variables for '{allyes/allmod/allno/rand}config'


            KCONFIG_ALLCONFIG

            
            --------------------------------------------------

            
            (partially based on lkml email from/by Rob Landley, re: miniconfig)

            
            --------------------------------------------------

            
            The allyesconfig/allmodconfig/allnoconfig/randconfig variants can also

            
            use the environment variable KCONFIG_ALLCONFIG as a flag or a filename

            
            that contains config symbols that the user requires to be set to a

            
            specific value.  If KCONFIG_ALLCONFIG is used without a filename where

            
            KCONFIG_ALLCONFIG == "" or KCONFIG_ALLCONFIG == "1", "make *config"

            
            checks for a file named "all{yes/mod/no/def/random}.config"

            
            (corresponding to the *config command that was used) for symbol values

            
            that are to be forced.  If this file is not found, it checks for a

            
            file named "all.config" to contain forced values.


            This enables you to create "miniature" config (miniconfig) or custom

            
            config files containing just the config symbols that you are interested

            
            in.  Then the kernel config system generates the full .config file,

            
            including symbols of your miniconfig file.


            This 'KCONFIG_ALLCONFIG' file is a config file which contains

            
            (usually a subset of all) preset config symbols.  These variable

            
            settings are still subject to normal dependency checks.


            Examples:

            
            	KCONFIG_ALLCONFIG=custom-notebook.config make allnoconfig

            
            or

            
            	KCONFIG_ALLCONFIG=mini.config make allnoconfig

            
            or

            
            	make KCONFIG_ALLCONFIG=mini.config allnoconfig


            These examples will disable most options (allnoconfig) but enable or

            
            disable the options that are explicitly listed in the specified

            
            mini-config files.


            ______________________________________________________________________

            
            Environment variables for 'randconfig'


            KCONFIG_SEED

            
            --------------------------------------------------

            
            You can set this to the integer value used to seed the RNG, if you want

            
            to somehow debug the behaviour of the kconfig parser/frontends.

            
            If not set, the current time will be used.


            KCONFIG_PROBABILITY

            
            --------------------------------------------------

            
            This variable can be used to skew the probabilities. This variable can

            
            be unset or empty, or set to three different formats:

            
            	KCONFIG_PROBABILITY     y:n split           y:m:n split

            
            	-----------------------------------------------------------------

            
            	unset or empty          50  : 50            33  : 33  : 34

            
            	N                        N  : 100-N         N/2 : N/2 : 100-N

            
                [1] N:M                     N+M : 100-(N+M)      N  :  M  : 100-(N+M)

            
                [2] N:M:L                    N  : 100-N          M  :  L  : 100-(M+L)


            where N, M and L are integers (in base 10) in the range [0,100], and so

            
            that:

            
                [1] N+M is in the range [0,100]

            
                [2] M+L is in the range [0,100]


            Examples:

            
            	KCONFIG_PROBABILITY=10

            
            		10% of booleans will be set to 'y', 90% to 'n'

            
            		5% of tristates will be set to 'y', 5% to 'm', 90% to 'n'

            
            	KCONFIG_PROBABILITY=15:25

            
            		40% of booleans will be set to 'y', 60% to 'n'

            
            		15% of tristates will be set to 'y', 25% to 'm', 60% to 'n'

            
            	KCONFIG_PROBABILITY=10:15:15

            
            		10% of booleans will be set to 'y', 90% to 'n'

            
            		15% of tristates will be set to 'y', 15% to 'm', 70% to 'n'


            ______________________________________________________________________

            
            Environment variables for 'silentoldconfig'


            KCONFIG_NOSILENTUPDATE

            
            --------------------------------------------------

            
            If this variable has a non-blank value, it prevents silent kernel

            
            config updates (requires explicit updates).


            KCONFIG_AUTOCONFIG

            
            --------------------------------------------------

            
            This environment variable can be set to specify the path & name of the

            
            "auto.conf" file.  Its default value is "include/config/auto.conf".


            KCONFIG_TRISTATE

            
            --------------------------------------------------

            
            This environment variable can be set to specify the path & name of the

            
            "tristate.conf" file.  Its default value is "include/config/tristate.conf".


            KCONFIG_AUTOHEADER

            
            --------------------------------------------------

            
            This environment variable can be set to specify the path & name of the

            
            "autoconf.h" (header) file.

            
            Its default value is "include/generated/autoconf.h".


            ======================================================================

            
            menuconfig

            
            --------------------------------------------------


            SEARCHING for CONFIG symbols


            Searching in menuconfig:


            	The Search function searches for kernel configuration symbol

            
            	names, so you have to know something close to what you are

            
            	looking for.


            	Example:

            
            		/hotplug

            
            		This lists all config symbols that contain "hotplug",

            
            		e.g., HOTPLUG_CPU, MEMORY_HOTPLUG.


            	For search help, enter / followed TAB-TAB-TAB (to highlight

            
            	<Help>) and Enter.  This will tell you that you can also use

            
            	regular expressions (regexes) in the search string, so if you

            
            	are not interested in MEMORY_HOTPLUG, you could try


            		/^hotplug


            	When searching, symbols are sorted thus:

            
            	  - first, exact matches, sorted alphabetically (an exact match

            
            	    is when the search matches the complete symbol name);

            
            	  - then, other matches, sorted alphabetically.

            
            	For example: ^ATH.K matches:

            
            	    ATH5K ATH9K ATH5K_AHB ATH5K_DEBUG [...] ATH6KL ATH6KL_DEBUG

            
            	    [...] ATH9K_AHB ATH9K_BTCOEX_SUPPORT ATH9K_COMMON [...]

            
            	of which only ATH5K and ATH9K match exactly and so are sorted

            
            	first (and in alphabetical order), then come all other symbols,

            
            	sorted in alphabetical order.


            ______________________________________________________________________

            
            User interface options for 'menuconfig'


            MENUCONFIG_COLOR

            
            --------------------------------------------------

            
            It is possible to select different color themes using the variable

            
            MENUCONFIG_COLOR.  To select a theme use:


            	make MENUCONFIG_COLOR=<theme> menuconfig


            Available themes are:

            
              mono       => selects colors suitable for monochrome displays

            
              blackbg    => selects a color scheme with black background

            
              classic    => theme with blue background. The classic look

            
              bluetitle  => a LCD friendly version of classic. (default)


            MENUCONFIG_MODE

            
            --------------------------------------------------

            
            This mode shows all sub-menus in one large tree.


            Example:

            
            	make MENUCONFIG_MODE=single_menu menuconfig


            ======================================================================

            
            xconfig

            
            --------------------------------------------------


            Searching in xconfig:


            	The Search function searches for kernel configuration symbol

            
            	names, so you have to know something close to what you are

            
            	looking for.


            	Example:

            
            		Ctrl-F hotplug

            
            	or

            
            		Menu: File, Search, hotplug


            	lists all config symbol entries that contain "hotplug" in

            
            	the symbol name.  In this Search dialog, you may change the

            
            	config setting for any of the entries that are not grayed out.

            
            	You can also enter a different search string without having

            
            	to return to the main menu.


            ======================================================================

            
            gconfig

            
            --------------------------------------------------


            Searching in gconfig:


            	None (gconfig isn't maintained as well as xconfig or menuconfig);

            
            	however, gconfig does have a few more viewing choices than

            
            	xconfig does.


            ###
	This file contains some assistance for using "make *config".

	Use "make help" to list all of the possible configuration targets.

	The xconfig ('qconf') and menuconfig ('mconf') programs also
	have embedded help text. Be sure to check it for navigation,
	search, and other general help text.

	======================================================================
	General
	--------------------------------------------------

	New kernel releases often introduce new config symbols. Often more
	important, new kernel releases may rename config symbols. When
	this happens, using a previously working .config file and running
	"make oldconfig" won't necessarily produce a working new kernel
	for you, so you may find that you need to see what NEW kernel
	symbols have been introduced.

	To see a list of new config symbols when using "make oldconfig", use

	cp user/some/old.config .config
	make listnewconfig

	and the config program will list any new symbols, one per line.

	scripts/diffconfig .config.old .config \| less

	______________________________________________________________________
	Environment variables for '*config'

	KCONFIG_CONFIG
	--------------------------------------------------
	This environment variable can be used to specify a default kernel config
	file name to override the default name of ".config".

	KCONFIG_OVERWRITECONFIG
	--------------------------------------------------
	If you set KCONFIG_OVERWRITECONFIG in the environment, Kconfig will not
	break symlinks when .config is a symlink to somewhere else.

	CONFIG_
	--------------------------------------------------
	If you set CONFIG_ in the environment, Kconfig will prefix all symbols
	with its value when saving the configuration, instead of using the default,
	"CONFIG_".

	______________________________________________________________________
	Environment variables for '{allyes/allmod/allno/rand}config'

	KCONFIG_ALLCONFIG
	--------------------------------------------------
	(partially based on lkml email from/by Rob Landley, re: miniconfig)
	--------------------------------------------------
	The allyesconfig/allmodconfig/allnoconfig/randconfig variants can also
	use the environment variable KCONFIG_ALLCONFIG as a flag or a filename
	that contains config symbols that the user requires to be set to a
	specific value. If KCONFIG_ALLCONFIG is used without a filename where
	KCONFIG_ALLCONFIG == "" or KCONFIG_ALLCONFIG == "1", "make *config"
	checks for a file named "all{yes/mod/no/def/random}.config"
	(corresponding to the *config command that was used) for symbol values
	that are to be forced. If this file is not found, it checks for a
	file named "all.config" to contain forced values.

	This enables you to create "miniature" config (miniconfig) or custom
	config files containing just the config symbols that you are interested
	in. Then the kernel config system generates the full .config file,
	including symbols of your miniconfig file.

	This 'KCONFIG_ALLCONFIG' file is a config file which contains
	(usually a subset of all) preset config symbols. These variable
	settings are still subject to normal dependency checks.

	Examples:
	KCONFIG_ALLCONFIG=custom-notebook.config make allnoconfig
	or
	KCONFIG_ALLCONFIG=mini.config make allnoconfig
	or
	make KCONFIG_ALLCONFIG=mini.config allnoconfig

	These examples will disable most options (allnoconfig) but enable or
	disable the options that are explicitly listed in the specified
	mini-config files.

	______________________________________________________________________
	Environment variables for 'randconfig'

	KCONFIG_SEED
	--------------------------------------------------
	You can set this to the integer value used to seed the RNG, if you want
	to somehow debug the behaviour of the kconfig parser/frontends.
	If not set, the current time will be used.

	KCONFIG_PROBABILITY
	--------------------------------------------------
	This variable can be used to skew the probabilities. This variable can
	be unset or empty, or set to three different formats:
	KCONFIG_PROBABILITY y:n split y:m:n split
	-----------------------------------------------------------------
	unset or empty 50 : 50 33 : 33 : 34
	N N : 100-N N/2 : N/2 : 100-N
	[1] N:M N+M : 100-(N+M) N : M : 100-(N+M)
	[2] N:M:L N : 100-N M : L : 100-(M+L)

	where N, M and L are integers (in base 10) in the range [0,100], and so
	that:
	[1] N+M is in the range [0,100]
	[2] M+L is in the range [0,100]

	Examples:
	KCONFIG_PROBABILITY=10
	10% of booleans will be set to 'y', 90% to 'n'
	5% of tristates will be set to 'y', 5% to 'm', 90% to 'n'
	KCONFIG_PROBABILITY=15:25
	40% of booleans will be set to 'y', 60% to 'n'
	15% of tristates will be set to 'y', 25% to 'm', 60% to 'n'
	KCONFIG_PROBABILITY=10:15:15
	10% of booleans will be set to 'y', 90% to 'n'
	15% of tristates will be set to 'y', 15% to 'm', 70% to 'n'

	______________________________________________________________________
	Environment variables for 'silentoldconfig'

	KCONFIG_NOSILENTUPDATE
	--------------------------------------------------
	If this variable has a non-blank value, it prevents silent kernel
	config updates (requires explicit updates).

	KCONFIG_AUTOCONFIG
	--------------------------------------------------
	This environment variable can be set to specify the path & name of the
	"auto.conf" file. Its default value is "include/config/auto.conf".

	KCONFIG_TRISTATE
	--------------------------------------------------
	This environment variable can be set to specify the path & name of the
	"tristate.conf" file. Its default value is "include/config/tristate.conf".

	KCONFIG_AUTOHEADER
	--------------------------------------------------
	This environment variable can be set to specify the path & name of the
	"autoconf.h" (header) file.
	Its default value is "include/generated/autoconf.h".


	======================================================================
	menuconfig
	--------------------------------------------------

	SEARCHING for CONFIG symbols

	Searching in menuconfig:

	The Search function searches for kernel configuration symbol
	names, so you have to know something close to what you are
	looking for.

	Example:
	/hotplug
	This lists all config symbols that contain "hotplug",
	e.g., HOTPLUG_CPU, MEMORY_HOTPLUG.

	For search help, enter / followed TAB-TAB-TAB (to highlight
	<Help>) and Enter. This will tell you that you can also use
	regular expressions (regexes) in the search string, so if you
	are not interested in MEMORY_HOTPLUG, you could try

	/^hotplug

	When searching, symbols are sorted thus:
	- first, exact matches, sorted alphabetically (an exact match
	is when the search matches the complete symbol name);
	- then, other matches, sorted alphabetically.
	For example: ^ATH.K matches:
	ATH5K ATH9K ATH5K_AHB ATH5K_DEBUG [...] ATH6KL ATH6KL_DEBUG
	[...] ATH9K_AHB ATH9K_BTCOEX_SUPPORT ATH9K_COMMON [...]
	of which only ATH5K and ATH9K match exactly and so are sorted
	first (and in alphabetical order), then come all other symbols,
	sorted in alphabetical order.

	______________________________________________________________________
	User interface options for 'menuconfig'

	MENUCONFIG_COLOR
	--------------------------------------------------
	It is possible to select different color themes using the variable
	MENUCONFIG_COLOR. To select a theme use:

	make MENUCONFIG_COLOR=<theme> menuconfig

	Available themes are:
	mono => selects colors suitable for monochrome displays
	blackbg => selects a color scheme with black background
	classic => theme with blue background. The classic look
	bluetitle => a LCD friendly version of classic. (default)

	MENUCONFIG_MODE
	--------------------------------------------------
	This mode shows all sub-menus in one large tree.

	Example:
	make MENUCONFIG_MODE=single_menu menuconfig


	======================================================================
	xconfig
	--------------------------------------------------

	Searching in xconfig:

	The Search function searches for kernel configuration symbol
	names, so you have to know something close to what you are
	looking for.

	Example:
	Ctrl-F hotplug
	or
	Menu: File, Search, hotplug

	lists all config symbol entries that contain "hotplug" in
	the symbol name. In this Search dialog, you may change the
	config setting for any of the entries that are not grayed out.
	You can also enter a different search string without having
	to return to the main menu.


	======================================================================
	gconfig
	--------------------------------------------------

	Searching in gconfig:

	None (gconfig isn't maintained as well as xconfig or menuconfig);
	however, gconfig does have a few more viewing choices than
	xconfig does.

	###