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Date:   Fri, 8 May 2020 16:04:39 -0300
From:   Jason Gunthorpe <jgg@mellanox.com>
To:     Arnd Bergmann <arnd@arndb.de>
Cc:     Ben Skeggs <bskeggs@redhat.com>,
        Felix Kuehling <Felix.Kuehling@amd.com>,
        Christoph Hellwig <hch@lst.de>,
        John Hubbard <jhubbard@nvidia.com>,
        David Airlie <airlied@linux.ie>,
        Daniel Vetter <daniel@ffwll.ch>,
        Dan Williams <dan.j.williams@intel.com>,
        Ira Weiny <ira.weiny@intel.com>,
        dri-devel <dri-devel@lists.freedesktop.org>,
        ML nouveau <nouveau@lists.freedesktop.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 2/2] nouveau: fix dependencies for DEVICE_PRIVATE
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On Fri, May 08, 2020 at 05:05:03PM +0200, Arnd Bergmann wrote:
> On Fri, May 8, 2020 at 5:00 PM Jason Gunthorpe <jgg@mellanox.com> wrote:
> >
> > On Fri, May 08, 2020 at 04:40:09PM +0200, Arnd Bergmann wrote:
> > > CONFIG_DEVICE_PRIVATE cannot be selected in configurations
> > > without ZONE_DEVICE:
> >
> > It is kind of unfortunate to lift dependencies from DEVICE_PRIVATE
> > into the users, is this really how kconfig is supposed to work or is
> > something else wrong here?
> 
> Usually the problem is trying to use 'select' for something that can
> be done with 'depends on'. I have actually no idea what
> CONFIG_DEVICE_PRIVATE does, as it lacks a help text
> and is a rather generic term.

It is a sub mode of ZONE_DEVICE, ie DEVICE_PRIVATE turns on a certain
kind of ZONE_DEVICE page.

Both ZONE_DEVICE and DEVICE_PRIVATE are APIs families drivers use,
there is no reason for a user to select either of these directly.

Jason