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From:   Dave Airlie <airlied@gmail.com>
Date:   Thu, 24 Jan 2019 07:57:11 +1000
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Subject: Re: [PATCH 00/15] Habana Labs kernel driver
To:     Oded Gabbay <oded.gabbay@gmail.com>,
        Jerome Glisse <jglisse@redhat.com>
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        LKML <linux-kernel@vger.kernel.org>, ogabbay@habana.ai
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On Wed, 23 Jan 2019 at 10:01, Oded Gabbay <oded.gabbay@gmail.com> wrote:
>
> Hello,
>
> For those who don't know me, my name is Oded Gabbay (Kernel Maintainer
> for AMD's amdkfd driver, worked at RedHat's Desktop group) and I work at
> Habana Labs since its inception two and a half years ago.

Hey Oded,

So this creates a driver with a userspace facing API via ioctls.
Although this isn't a "GPU" driver we have a rule in the graphics
drivers are for accelerators that we don't merge userspace API with an
appropriate userspace user.

https://dri.freedesktop.org/docs/drm/gpu/drm-uapi.html#open-source-userspace-requirements

I see nothing in these accelerator drivers that make me think we
should be treating them different.

Having large closed userspaces that we have no insight into means we
get suboptimal locked for ever uAPIs. If someone in the future creates
an open source userspace, we will end up in a place where they get
suboptimal behaviour because they are locked into a uAPI that we can't
change.

Dave.