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From:   Hridya Valsaraju <hridya@google.com>
Date:   Thu, 27 Aug 2020 10:21:51 -0700
Message-ID: <CA+wgaPO-WqMcvsEHZ926eKfvcCwfgDwT+Cg4A-JvEpA5xTwDNA@mail.gmail.com>
Subject: Re: [PATCH] staging: ion: remove from the tree
To:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc:     Amit Pundir <amit.pundir@linaro.org>,
        "open list:ANDROID DRIVERS" <devel@driverdev.osuosl.org>,
        Christoph Hellwig <hch@infradead.org>,
        Android Kernel Team <kernel-team@android.com>,
        Todd Kjos <tkjos@android.com>,
        Martijn Coenen <maco@android.com>,
        lkml <linux-kernel@vger.kernel.org>,
        dri-devel <dri-devel@lists.freedesktop.org>,
        =?UTF-8?Q?Christian_K=C3=B6nig?= <christian.koenig@amd.com>,
        linaro-mm-sig@lists.linaro.org,
        Joel Fernandes <joel@joelfernandes.org>,
        =?UTF-8?B?QXJ2ZSBIasO4bm5ldsOlZw==?= <arve@android.com>,
        John Stultz <john.stultz@linaro.org>,
        Suren Baghdasaryan <surenb@google.com>,
        Laura Abbott <laura@labbott.name>,
        Shuah Khan <shuah@kernel.org>,
        Sumit Semwal <sumit.semwal@linaro.org>,
        Christian Brauner <christian@brauner.io>
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On Thu, Aug 27, 2020 at 10:17 AM Greg Kroah-Hartman
<gregkh@linuxfoundation.org> wrote:
>
> On Thu, Aug 27, 2020 at 10:31:41PM +0530, Amit Pundir wrote:
> > On Thu, 27 Aug 2020 at 21:34, Greg Kroah-Hartman
> > <gregkh@linuxfoundation.org> wrote:
> > >
> > > On Thu, Aug 27, 2020 at 09:31:27AM -0400, Laura Abbott wrote:
> > > > On 8/27/20 8:36 AM, Greg Kroah-Hartman wrote:
> > > > > The ION android code has long been marked to be removed, now that=
 we
> > > > > dma-buf support merged into the real part of the kernel.
> > > > >
> > > > > It was thought that we could wait to remove the ion kernel at a l=
ater
> > > > > time, but as the out-of-tree Android fork of the ion code has div=
erged
> > > > > quite a bit, and any Android device using the ion interface uses =
that
> > > > > forked version and not this in-tree version, the in-tree copy of =
the
> > > > > code is abandonded and not used by anyone.
> > > > >
> > > > > Combine this abandoned codebase with the need to make changes to =
it in
> > > > > order to keep the kernel building properly, which then causes mer=
ge
> > > > > issues when merging those changes into the out-of-tree Android co=
de, and
> > > > > you end up with two different groups of people (the in-kernel-tre=
e
> > > > > developers, and the Android kernel developers) who are both annoy=
ed at
> > > > > the current situation.  Because of this problem, just drop the in=
-kernel
> > > > > copy of the ion code now, as it's not used, and is only causing p=
roblems
> > > > > for everyone involved.
> > > > >
> > > > > Cc: "Arve Hj=C3=B8nnev=C3=A5g" <arve@android.com>
> > > > > Cc: "Christian K=C3=B6nig" <christian.koenig@amd.com>
> > > > > Cc: Christian Brauner <christian@brauner.io>
> > > > > Cc: Christoph Hellwig <hch@infradead.org>
> > > > > Cc: Hridya Valsaraju <hridya@google.com>
> > > > > Cc: Joel Fernandes <joel@joelfernandes.org>
> > > > > Cc: John Stultz <john.stultz@linaro.org>
> > > > > Cc: Laura Abbott <laura@labbott.name>
> > > > > Cc: Martijn Coenen <maco@android.com>
> > > > > Cc: Shuah Khan <shuah@kernel.org>
> > > > > Cc: Sumit Semwal <sumit.semwal@linaro.org>
> > > > > Cc: Suren Baghdasaryan <surenb@google.com>
> > > > > Cc: Todd Kjos <tkjos@android.com>
> > > > > Cc: devel@driverdev.osuosl.org
> > > > > Cc: dri-devel@lists.freedesktop.org
> > > > > Cc: linaro-mm-sig@lists.linaro.org
> > > > > Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> > > >
> > > > We discussed this at the Android MC on Monday and the plan was to
> > > > remove it after the next LTS release.
> > >
> > > I know it was discussed, my point is that it is actually causing
> > > problems now (with developers who want to change the internal kernel =
api
> > > hitting issues, and newbies trying to clean up code in ways that isn'=
t
> > > exactly optimal wasting maintainer cycles), and that anyone who uses
> > > this code, is not actually using this version of the code.  Everyone =
who
> > > relies on ion right now, is using the version that is in the Android
> > > common kernel tree, which has diverged from this in-kernel way quite =
a
> > > bit now for the reason that we didn't want to take any of those new
> > > features in the in-kernel version.
> > >
> > > So this is a problem that we have caused by just wanting to wait, no =
one
> > > is using this code, combined with it causing problems for the upstrea=
m
> > > developers.
> > >
> > > There is nothing "magic" about the last kernel of the year that requi=
res
> > > this code to sit here until then.  At that point in time, all users
> > > will, again, be using the forked Android kernel version, and if we
> > > delete this now here, that fork can remain just fine, with the added
> > > benifit of it reducing developer workloads here in-kernel.
> > >
> > > So why wait?
> >
> > Hi,
> >
> > I don't know what is the right thing to do here. I just want to
> > highlight that AOSP's audio (codec2) HAL depends on the ION system
> > heap and it will break AOSP for people who boot mainline on their
> > devices, even for just testing purpose like we do in Linaro. Right now
> > we need only 1 (Android specific out-of-tree) patch to boot AOSP with
> > mainline and Sumit is already trying to upstream that vma naming
> > patch. Removal of in-kernel ION, will just add more to that delta.
>
> As AOSP will continue to rely on ION after December of this year, all
> you are doing is postponing the inevitable a few more months.
>
> Push back on the Android team to fix up the code to not use ION, they
> know this needs to happen.
>

Hi all,

We are currently working with the codec2 team to transition codec2 to
use libdmabufheap instead of libion. It will definitely happen during
the Android S timeframe.

Thanks,
Hridya

> thanks,
>
> greg k-h