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From:   Arnd Bergmann <arnd@arndb.de>
Date:   Thu, 23 Apr 2020 17:28:08 +0200
Message-ID: <CAK8P3a0ydfp79Us-WhwwHOB2MGgtj=ovfYa_g8qhazA4gmv8eg@mail.gmail.com>
Subject: Re: [RFC PATCH 1/2] Kconfig: Introduce "uses" keyword
To:     Jason Gunthorpe <jgg@ziepe.ca>
Cc:     Nicolas Pitre <nico@fluxnic.net>,
        Randy Dunlap <rdunlap@infradead.org>,
        Jani Nikula <jani.nikula@linux.intel.com>,
        Saeed Mahameed <saeedm@mellanox.com>,
        "masahiroy@kernel.org" <masahiroy@kernel.org>,
        "Laurent.pinchart@ideasonboard.com" 
        <Laurent.pinchart@ideasonboard.com>,
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On Thu, Apr 23, 2020 at 5:16 PM Jason Gunthorpe <jgg@ziepe.ca> wrote:
> On Thu, Apr 23, 2020 at 11:11:46AM -0400, Nicolas Pitre wrote:

> > > > I don't see how that one can be helped. The MTD dependency is not
> > > > optional.
> > >
> > > Could it be done as
> > >
> > > config MTD
> > >    depends on CRAMFS if CRAMFS_MTD
> > >
> > > ?
> >
> > No. There is no logic in restricting MTD usage based on CRAMFS or
> > CRAMFS_MTD.
>
> Ah, I got it backwards, maybe this:
>
> config CRAMFS
>    depends on MTD if CRAMFS_MTD

I'm not sure this can work if you also have the requirement that 'CRAMFS_MTD
depends on CRAMFS': dependencies in Kconfig generally cannot have
loops in them.

       Arnd