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From:   Dave Airlie <airlied@gmail.com>
Date:   Thu, 24 Jan 2019 20:22:49 +1000
Message-ID: <CAPM=9twdfFSevH-qq7Vf1F7-nAgYvAw9XYmEKT-8LYBc403Thw@mail.gmail.com>
Subject: Re: [PATCH 00/15] Habana Labs kernel driver
To:     Oded Gabbay <oded.gabbay@gmail.com>
Cc:     Daniel Vetter <daniel.vetter@ffwll.ch>,
        Jerome Glisse <jglisse@redhat.com>,
        Olof Johansson <olof@lixom.net>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        LKML <linux-kernel@vger.kernel.org>, ogabbay@habana.ai,
        Arnd Bergmann <arnd@arndb.de>, fbarrat@linux.ibm.com,
        Andrew Donnellan <andrew.donnellan@au1.ibm.com>
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> I know I won't be able to convince you but I want to say that I think
> your arguments for full userspace open source are not really
> technical.

There is more to keeping a kernel going than technical argument unfortunately.

I guess the question for Greg, Olof etc, is do we care about Linux the
kernel, or Linux the open source ecosystem, if the former, these sort
of accelerator shim drivers are fine, useless to anyone who doesn't
have all the magic hidden userspace, and impossible to support for
anyone else, if the latter, we should leave the cost of maintenance to
the company benefiting from it and leave maintaining it out of tree.

Simple question like If I plug your accelerator into Power or ARM64,
where do I get the port of your userspace to use it?

I'm not the final arbiter on this sort of thing, but I'm definitely
going to make sure that anyone who lands this code is explicit in
ignoring any experience we've had in this area and in the future will
gladly accept "I told you so" :-)

Dave.