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From:   Rob Herring <robh@kernel.org>
Date:   Mon, 10 Jun 2019 09:38:50 -0600
Message-ID: <CAL_Jsq+KpJHgyx017u78+D0HX03NNJuK=fYVES5J1dEpQroeEQ@mail.gmail.com>
Subject: Re: [PATCH v3 2/2] drm/panfrost: Use drm_gem_shmem_map_offset()
To:     Steven Price <steven.price@arm.com>
Cc:     Chris Wilson <chris@chris-wilson.co.uk>,
        Tomeu Vizoso <tomeu.vizoso@collabora.com>,
        David Airlie <airlied@linux.ie>,
        Seung-Woo Kim <sw0312.kim@samsung.com>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Krzysztof Kozlowski <krzk@kernel.org>,
        Maxime Ripard <maxime.ripard@bootlin.com>,
        Kyungmin Park <kyungmin.park@samsung.com>,
        Kukjin Kim <kgene@kernel.org>,
        dri-devel <dri-devel@lists.freedesktop.org>,
        Sean Paul <sean@poorly.run>,
        Alyssa Rosenzweig <alyssa@rosenzweig.io>
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On Wed, May 22, 2019 at 6:39 AM Steven Price <steven.price@arm.com> wrote:
>
> On 21/05/2019 19:23, Chris Wilson wrote:
> > Quoting Rob Herring (2019-05-21 16:24:27)
> >> On Mon, May 20, 2019 at 4:23 AM Steven Price <steven.price@arm.com> wrote:
> >>>
> >>
> >> You forgot to update the subject. I can fixup when applying, but I'd
> >> like an ack from Chris on patch 1.
>
> Sorry about that - I'll try to be more careful in the future.
>
> > I still think it is incorrect as the limitation is purely an issue with
> > the shmem backend and not a generic GEM limitation. It matters if you
>
> Do you prefer the previous version of this series[1] with the shmem helper?
>
> [1]
> https://lore.kernel.org/lkml/20190516141447.46839-1-steven.price@arm.com/
>
> Although this isn't a generic GEM limitation it's currently the same
> limitation that applies to the 'dumb' drivers as well as shmem backend,
> so I'd prefer not implementing two identical functions purely because
> this limitation could be removed in the future.

In interest of moving this forward, how about some comments in
drm_gem_map_offset() explaining the limitations and when it is
appropriate to use the function.

Rob