On Thu, Oct 20, 2016 at 03:52:04PM +0100, Edward Cree wrote: > On 20/10/16 00:42, Nicolas Pitre wrote: > > diff --git a/Documentation/kbuild/kconfig-language.txt b/Documentation/kbuild/kconfig-language.txt > > index 069fcb3eef..c96127f648 100644 > > --- a/Documentation/kbuild/kconfig-language.txt > > +++ b/Documentation/kbuild/kconfig-language.txt > > @@ -113,6 +113,33 @@ applicable everywhere (see syntax). > > That will limit the usefulness but on the other hand avoid > > the illegal configurations all over. > > > > +- weak reverse dependencies: "imply" <symbol> ["if" <expr>] > > + This is similar to "select" as it enforces a lower limit on another > > + symbol except that the "implied" config symbol's value may still be > > + set to n from a direct dependency or with a visible prompt. > > + Given the following example: > > + > > + config FOO > > + tristate > > + imply BAZ > > + > > + config BAZ > > + tristate > > + depends on BAr > > + > > + The following values are possible: > > + > > + FOO BAR BAR's default choice for BAZ > Should the third column not be "BAZ's default"? > > + --------------- --------------- --------------- -------------- > > + n y n N/m/y > > + m y m M/y/n > > + y y y Y/n > > + y n * N > Also, I don't think having any FOO=y should preclude BAZ=m. Suppose both > FOO and FOO2 imply BAZ, FOO=y and FOO2=m. Then if BAZ-features are only > desired for driver FOO2, BAz=m makes sense. That's exactly the problem that motivated "imply" in the first place: while that's *possible*, it means the user needs to know that they're breaking BAZ support for driver FOO. In theory, someone could extend the UI to note the symbols with an "imply" for a given symbol and provide additional help for the implied symbol that explains the implications. In that case, it might make sense to allow the user to explicitly mark a symbol as 'm', with appropriate explanations of the implications. But in the absence of that, the simple solution seems like preventing 'm' for a symbol implied by a symbol marked as 'y'. -- To unsubscribe from this list: send the line "unsubscribe linux-kbuild" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
