Re: [patch] MTD: fix DOC2000/2001/2001PLUS build error

From: Ingo Molnar
Date: Mon Feb 05 2007 - 11:31:01 EST



* David Woodhouse <dwmw2@xxxxxxxxxxxxx> wrote:

> No, it was MTD_NAND_CAFE which requires MTD_NAND, and that _is_ within
> the same tree. I don't know why you added it to the old monolithic
> DiskOnChip driver.

yeah, i mis-analyzed the point of breakage - and my Kconfig hack simply
papered it over by accident. I agree that your fix is the right one.

> > btw., this whole select problem is not limited to Aunt Tillie: in a
> > couple of cases in the past few months when i saw some weird code in
> > a driver and tried to enable it i had to search around for many
> > minutes and enable random options to figure out its config
> > dependencies until i had the driver truly enabled. (if there's some
> > easy solution to this then i'm all ears - but i exclude the easiest
> > solution of adding me to the 'aunt' category ;-)
>
> I come across this frequently -- and I just look at the Kconfig file
> to see the dependencies of the option I want to enable. It's usually
> very simple.

i come across this problem frequently, and sometimes it's far from
simple and involves half a dozen Kconfigs. For example pick up a Fedora
.config of your choice and disable CONFIG_I2C.

> It's got a _lot_ harder recently to turn stuff _off_, as rmk observes.
> You don't just look at the option you're interested in; you have to
> grep all over the rest of the tree to find the 'select' which is
> forcing it on after you turn it off. It's no longer in one place.

yeah.

> > I think that by blaming Aunt Tillie you might be missing the real
> > problem.
>
> No, by arbitrarily throwing 'select' into the mix with no real
> guidance as to when to use it and when to use normal dependencies,
> _that's_ when we're missing the real problem.

we should not have 'select' at all - unless it's some non-code option
that is just a convenience switch for several other config options. A
true dependency is already expressed in one direction via the 'depend
on' directive - no need to express it in the other direction as well,
that only leads to redundancy and to bugs.

Ingo
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