Re: Config.in question

[Andrzej Krzysztofowicz]

> Hello,
> 
> The PC300 driver supports X.25, but in order to support it, it depends on
> other drivers in the kernel (to be more exact, the other drivers are the
> "CCITT X.25 Packet Layer" -- CONFIG_X25 -- and the "LAPB Data Link Driver"
> -- CONFIG_LAPB).
> 
> Although this is mentioned in the help for the CONFIG_PC300_X25 option,
> I'd like to know if it's possible to set CONFIG_X25 and CONFIG_LAPB to "m"
> automatically as soon as CONFIG_PC300_X25 is set.
> 
> Something like:
> 
> bool '    Cyclades-PC300 X.25 support (please read help)' CONFIG_PC300_X25
> if [ "CONFIG_PC300_X25" = "y" ]; then
>   CONFIG_X25=m
>   CONFIG_LAPB=m
> fi

It *is* possible to use define_tristate here if the CONFIG_X25/CONFIG_LAPB
appear earlier in the configuration (ie. "define_tristate" for CONFIG_X25
can't precede "tristate" for CONFIG_X25). Simple VAR=value does NOT work.

However, it is not recomended as there is a trap here: you may have an
option that needs CONFIG_X25=m and another one that needs CONFIG_X25=n.
How do you control this when CONFIG_X25=y was set previously or you have
modules disabled ?
It makes config scripts very complicated and difficult to maintain.

Probably you should look at CML2 development page:
   http://www.tuxedo.org/~esr/kbuild

I think, CML2 has already included the feature you need, but it is a project
for 2.5+ ...

> Even if that's possible, I don't like this approach (I'd rather just
> mention it in the help). Nevertheless, I'd like to know whether it's
> possible or not.

--
=======================================================================
  Andrzej M. Krzysztofowicz               [e-mail]
  phone [phone]
Faculty of Applied Phys. & Math.,   Technical University of Gdansk