From bf83266a1eef8251e2f126dba635039de069104a Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Tue, 4 Jun 2024 01:19:02 +0900 Subject: kconfig: doc: fix a typo in the note about 'imply' This sentence does not make sense due to a typo. Fix it. Fixes: def2fbffe62c ("kconfig: allow symbols implied by y to become m") Signed-off-by: Masahiro Yamada Reviewed-by: Randy Dunlap --- Documentation/kbuild/kconfig-language.rst | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'Documentation') diff --git a/Documentation/kbuild/kconfig-language.rst b/Documentation/kbuild/kconfig-language.rst index 555c2f839969..86be5b857cc4 100644 --- a/Documentation/kbuild/kconfig-language.rst +++ b/Documentation/kbuild/kconfig-language.rst @@ -184,7 +184,7 @@ applicable everywhere (see syntax). ability to hook into a secondary subsystem while allowing the user to configure that subsystem out without also having to unset these drivers. - Note: If the combination of FOO=y and BAR=m causes a link error, + Note: If the combination of FOO=y and BAZ=m causes a link error, you can guard the function call with IS_REACHABLE():: foo_init() -- cgit From 45c7f555bf5e716d9c6ffb737e97d4cc9b4c21ef Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Tue, 4 Jun 2024 01:19:03 +0900 Subject: kconfig: doc: document behavior of 'select' and 'imply' followed by 'if' Documentation/kbuild/kconfig-language.rst explains the behavior of 'select' as follows: reverse dependencies can be used to force a lower limit of another symbol. The value of the current menu symbol is used as the minimal value can be set to. This is not true when the 'select' property is followed by 'if'. [Test Code] config MODULES def_bool y modules config A def_tristate y select C if B config B def_tristate m config C tristate [Result] CONFIG_MODULES=y CONFIG_A=y CONFIG_B=m CONFIG_C=m If "the value of A is used as the minimal value C can be set to", C must be 'y'. The actual behavior is "C is selected by (A && B)". The lower limit of C is downgraded due to B being 'm'. This behavior is kind of weird, and this has arisen several times in the mailing list. I do not know whether it is a bug or intended behavior. Anyway, it is not feasible to change it now because many Kconfig files are written based on this behavior. The same applies to 'imply'. Document this (but reserve the possibility for a future change). Signed-off-by: Masahiro Yamada Reviewed-by: Randy Dunlap --- Documentation/kbuild/kconfig-language.rst | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'Documentation') diff --git a/Documentation/kbuild/kconfig-language.rst b/Documentation/kbuild/kconfig-language.rst index 86be5b857cc4..1fb3f5e6193c 100644 --- a/Documentation/kbuild/kconfig-language.rst +++ b/Documentation/kbuild/kconfig-language.rst @@ -150,6 +150,12 @@ applicable everywhere (see syntax). That will limit the usefulness but on the other hand avoid the illegal configurations all over. + If "select" is followed by "if" , will be + selected by the logical AND of the value of the current menu symbol + and . This means, the lower limit can be downgraded due to the + presence of "if" . This behavior may seem weird, but we rely on + it. (The future of this behavior is undecided.) + - weak reverse dependencies: "imply" ["if" ] This is similar to "select" as it enforces a lower limit on another @@ -202,6 +208,10 @@ applicable everywhere (see syntax). imply BAR imply BAZ + Note: If "imply" is followed by "if" , the default of + will be the logical AND of the value of the current menu symbol and . + (The future of this behavior is undecided.) + - limiting menu display: "visible if" This attribute is only applicable to menu blocks, if the condition is -- cgit